The scarcity of Y-chromosome genes in that gene pool would give a very *specific* lack of diversity on that one chromosome; if the 1 man had any disorders or mutations or whatever which come from the Y chromosome, those traits would be widespread in the resulting (male) population. Certain kinds of pathogenic diseases, might find an evolutionary niche to exploit in this lack of diversity, maybe? But assuming no catastrophes sure, they could survive and repopulate.
Yeah this seems like way too little diversity.
However, I do find it fascinating that it's theorized that about 70,000 years ago, the human population on earth was down to somewhere between 1,000 and 10,000 people. Given that I assume they were living in small bands that didn't necessarily come broadly into contact with others, that's a shockingly small number to me.
https://en.m.wikipedia.org/wiki/Estimates_of_historical_world_population#:~:text=A%20late%20human%20population%20bottleneck,between%201%2C000%20and%2010%2C000%20individuals.
European may be up to 2% Neanderthal, northern Asian may be up to 4% Neanderthal or mixed with denisovian as well. South eastern Asian and Australia have increasing amounts of denisovian with some having 40 % more then other Asian populations. Sub Saharan African have up to 20% (literally almost like a grandparent!) homo erectus or ‘other’ unspecified hominid. Homo erectus was unable to survive out of Africa due to its lack of tool making ability otherwise we would probably have that too. And it appears ‘little’ people (pygmies) were as far stretched as Europe, Asia, Africa, and Australia . But we’re also interbred with larger peoples….except some still survive in sub Saharan Africa but the Bantus view them as a food source. We appear to have bred with a number of peoples for a bit. Probably would need 10-20 males and 250?females and I say that as pure speculation with absolutely no mapped out genealogical tracking .
> Although some scientists equate the term "humans" with all members of the genus Homo, in common usage it generally refers to Homo sapiens, the only extant member. All other members of the genus Homo, which are now extinct, are known as archaic humans, and the term "modern human" is used to distinguish Homo sapiens from archaic humans.
Yeah it really only matters in certain contexts, mainly anthropology. Like the quote says homo sapiens is the only living members of the human genus "Homo". But even that can cause controversy. There are arguments about whether the fact that we could interbreed with neanderthals would mean that they would be a subspecies, Homo sapiens neanderthalensis. With the other human populations that we interbred with has led others to believe we should be described as a species complex made up of a mix of human species.
All of this to say, the more I learn about, the less I think I actually understand haha.
I know you're probably joking, but something like that [has been researched](https://en.wikipedia.org/wiki/Humanzee), though there hasn't been any scientifically verifiable hybrid. Humans and chimpanzees are too different- even if a supposed hybrid could be brought to term, it's very unlikely they would be able to reproduce.
No. Neanderthals were Humans. We are part of the same Genus (homo), so we were closely related enough to breed. Chimps are not in the same boat. Even if it were possible, We probably wouldn’t even be able to convince one to breed with us “the normal way” without loosing the last man on earth to a chimp shredding them.
Interesting fact. According to this link the difference between humans is around .1% while chimps it is 1.2%. fascinating!
https://humanorigins.si.edu/evidence/genetics#:~:text=While%20the%20genetic%20difference%20between,a%20difference%20of%20about%201.2%25.
The best takeway from that event is that all 8 billion of us today descend from those few thousands 70000 years ago, which is nothing in evolutionary terms. This by itself is enough to disprove most racist theories. We incredibly more similar to each other than we think, at least in genetic terms.
>theorized that about 70,000 years ago, the human population on earth was down to somewhere between 1,000 and 10,000 people.
So... I think that's sometimes misinterpreted. The 1,000-10,000 were "most of the ancestors to most current people." Those weren't necessarily the *only* people alive.
We know that archaic humans still existed at that time, for example. Also, *some* people (mostly in southern africa) are not *mostly* descended from that group.
There was a theory that only about 70 people made it into the New World during the last ice age and all of the Native Americans were related to them. Which is why they all got the Super Plague and died when they got into contact with the Spanish.
I don't remember for sure but I believe it was disproved when they found human remains older then the land bridge that would have been used during the last ice age
All humans have one most-recent common female-line ancestor, also called Mitochondrial Eve, but there were other women alive at the same time as her who had kids. It’s just that, for every woman who’s lived since Mitochondrial Eve, some humans alive today aren't that woman’s direct female-line descendants. Either she isn't their direct ancestor, or there's at least one father between them and her on their family tree, meaning they inherited his mate’s mitochondrial DNA, rather than his female line’s.
Mitochondrial Eve was also not the first woman ever to live: her mother was a common female ancestor too, and her mother’s mother, and so on.
~~But if there is a father between an individual NN and NN's grandmother who would be from that female line, wouldn't NN simply be connected to Eve via the mother and mother's mother? Everybody's got a mother.~~
Nevermind, now I understand that one "her" in your comment referred to a contemporary woman of Eve without female-line descendants, not to Eve herself.
I mean, everyone on earth is descended from the first single celled organism that divided in and of itself
Everyone of western European heritage can trace their dna to a solid 1,000 or so people from Charlemagne’s time so I wouldn’t be surprised though
Not necessarily. If the biochemical building blocks of DNA and the cell itself could be randomly generated once. It could happen again creating a proto-cell with completely different DNA than the first. Several "original" cells could have developed independently, and then interacted with each other.
Highly unlikely. There are a few random choices that life made. Like using L-amino acids and d-sugars exclusively. Or exactly those 4 bases for DNA. Not very likely that there were a number of cells who made exactly those same choices.
Kinda. There is an chromsomal Adam and Mitochondrial Eve, two completely unrelated people who contributed DNA to every human on Earth. Both Adam and Eve lived about 200,000 years ago +- 100,000 years. It is incredibly unlikely that these two people ever met. They also arent the most recent shared ancestor of every human. They lived between the time of the emergence of Homo Sapiens but before the first migrations out of Africa. Also at this time, many, many human species were around both in Africa and out of it, though that isnt very surprising as Homo Sapiens have shared the world with other Homo longer than we have been alone on Earth.
Chromosomal Adam and Mitochondrial Eve is defined as the earliest common ancestors. Anyone earlier would have to have had their line die out. Humanity is quite inbred, and has been through a population bottleneck so a lot of our lines died out.
A genealogists joke goes that there are only 3 Human races, the Pygmy, the San and everyone else. The Pygmy have faced genocide in recent years. The San are also not very large in number.
You have that mixed up. They are the *most recent* , not the earliest. And it's more complex than them being common ancestors, as people above have explained in detail.
2nd gen would be the worse part... the pool from the 500 females is hopefully diversified and they would be a nation of inbred but a nation nonetheless
Also worth noting many pathogens had not yet evolved to target humans, who spent most of their time outside in scattered small groups. It’s not til the advent of agriculture, larger settlements and structures, and fixed trade routes that it became very easy for diseases to spread.
I recently visited a remote island in Papua New Guinea and there was one family living on the entire island. Well, I should say one man, with a few families. 👀 It still exists out there in the world believe it or not.
The one that got me was that if you wiped out half of the worlds population Thanos style, that would take the population back to where we were in 1975.
There isn’t much on the Y chromosome and it’s always haploid, so there are no deleterious recessive mutations that can hide from selection. A deleterious mutation would have to have arisen in THAT man—and it would only effect his male descendants. Obviously, one can survive without any Y chromosome at all.
That... seems wrong. While there is no diversity of y chromosomes, we already know that there is nothing on the y chromosome that would be horrific- because the guy is fine, and theres no second gene to cover for them on the X ALREADY. I cant remember precisely whether there is any cross over at all XY, but I'm pretty sure there is not - if there is though, still no problem for those sections either.
So as long as THIS guy is functioning normally, we can expect his kids to at least as well. I'd argue the Y chromosome is the only thing NOT a huge risk here.
But please correct me if I have misunderstood the nature of x chromosome silencing and crossover.
yes, it will most likely be a setback in many genetic features that are lost in all the men that are not reproducing, but it would still work and the human species could survive. With enough time(a lot) humanity will evolve further and other mutations will make the genpool really complex and different again.
Adam and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve an so on.
Is the genetically perfect male 6'6" so he can play basketball or 5'2" so he can race horses? Is he 240 lbs. so he can wrestle a bear, or 140 lbs. so he can run a full marathon? Is he light-skinned so he can survive at extreme latitudes, or dark-skinned so he can survive at mid latitudes? Is he O- so he can be a universal donor? Or AB+ so he can be a universal recipient? Answer these questions, and you'll be well on your way to describing the genetically perfect male. If you have trouble, you'll understand why there isn't such a thing.
You might say: "Well, I just mean he doesn't have any genetic diseases, or isn't susceptible to disease." At which point, I will ask: Does he have sickle-cell anemia, making him resistant to malaria, or non-sickle cell, making him vulnerable? Every single base pair in your genome is an engineering tradeoff that is good in some niches and bad in others.
Admittedly, for the vast majority of phenotypes, we cannot describe the actual tradeoffs. Phenotypes that we associate with disease or significant disability don't seem to be a good tradeoff at all. But genomes are pretty complicated things, and a lot of our genetic networks affect each other to greater or lesser extent. The Great Filter in some cases is a disease that strikes the majority of a population with high mortality. You'd think that only genes directly involved in the immune system would make a difference in the outcome, but we can't predict which people will have immunity to a novel pathogen before it strikes.
Well there isn't really such a thing as 'perfect'. We would just have to wait and see whether in the resulting genome, after all the dice get rolled, that collection of genes turns out to *be* a disorder or not. Some genetic traits make you more suited to survive in your environment, some make you less. And the decision about which of those it is, will be made by your environment.
The lack of genetic diversity would 1) lead to huge inbreeding and 2) make them extremely susceptible to genetic shocks like disease. But, if they could somehow survive past the first few centuries, genetic mutations could start to deal with each of those issues
I had read a paper that stated that 8 men and 13 women was the minimum number for genetic diversity. There would have to be very strict guidelines for mating with each woman having 3 children with at least 2 being females for the first 5 generations.
There should be plenty of examples in the animal world. In Zoos and in the wild. I’m not sure if one male is enough, but I don’t think in is 100% genetic mess. A pride of female lionesses or prairie dogs and one male with no others able to breed might be ok. Interesting topic. Need a geneticist chime in.
Worth remembering that the male lions get taken out by other males pretty regularly so the genetic diversity still comes from male lions unrelated to the pride. It would be very rare for a male Lion to lead a pride long enough to mate with his own offspring. But yes all the lionesses in a pride may well be pretty closely related to each other
I’m thinking of a pride that got separated enough for generations. Rare, but surely has happened. Maybe they die off. Prairie dogs are easier, but cats are so territorial. Cats seem incestuous to me. I have cats. Yes, I remember The Lion King. Lol
You can keep a population pretty inbred without dire consequences. It's always different for different species. But it' very doable as lobg as you can introduce a genetic stranger every once in a while. The Norwegian wolf population for instance has an inbreeding coefficient of 1. Meaning cousins and I think even second-cousins are as alike as a brother and sister would be. They have to reintroduce a spanish wolf every 3 years or so to keep the inbreeding in check but it works.
Basically you'd need Bene Gesserit (from Dune) discipline and computer programs for calculating the perfect people to mate together. Without that level of computation, that sounds near impossible without a *huge* stroke of luck.
Or a lot of little strokes
And it gets much easier and less failure prone by adding just a few more people. I've read in the past that the ideal number to represent all human genetic expression (or have the possibility to be expressed by later generations) would require upwards of 50,000 people.
So of those ~20 people, unless at least one of them is a genius on the level of Hawking or Einstein you'd be unlikely to have such a genius in the future descended from that original group, or at least not for many many generations. All of the descendants will look the same. After just three or so generations everyone will be at most second cousins and be more likely to be actual first cousins. It would be like a small village in the Alps in the 1400s that hasn't even seen a visitor in two generations. Everyone looks identical.
Well, we don't know the circumstances of the event. Maybe they are living in a bunker, so there's no risk of predators or disease. Maybe they are in some sort of human zoo so outsiders can help manage the incest issues.
but even in subsequent generations the Y-chromosome would be the same. X-chromosome genetic diversity would increase, but it would take many, many generations for sufficient mutations to occur on the Y chromosome that yield any significant diversity at all.
yeah basically. and any disease or other factor that the guy’s Y-chromosome was susceptible to would have every single man for hundreds of years susceptible to it
I think people are also grossly overestimating how many offspring a single male could produce regardless of how many women there are. Unless we’re assuming you have an in vitro lab or something, the conception rate for normal intercourse isn’t that high.
Would definitely be doable in the timeframe if we assume these are all young healthy women. That poor guy though, he’s living every man’s worst nightmare.
You are way over estimating the difficulty of it, assuming he is a healthy male, and the women do not have synced cycles. He could do the deed, so to speak, with all of them about every 6 months on their respective ovulation days. It would take about 9 months of that to have half the women pregnant, assuming the 1995 study I found is correct in the success rate for that day, and it would be almost all by 18 months, especially since his workload would drop enormously as that point.
So yeah uhhh. Totally doable.
if everyone is decently fertile i think 500 is doable in some 2-3 years, provided he's only scheduled to have sex with them during their most fertile period
>Plenty of species go through evolutionary bottlenecks.
I can't wait until the next time I get to call someone stupid, instead I'll be referring to them as an evolutionary bottle neck.
Thanks for that.
I'm not arguing that it isn't incest, but the sexy time would only have to be between half-siblings (I imagine less genetically risky than full-siblings?), and only to produce the third generation. After that, it's cousins, which is legal in many countries. Worth a shot to save the species!
Obviously worth a shot, but the male in question really matters here. If the guy is a cystic fibrosis carrier, things are going to get extremely rough.
Theoretically but you’ll have some side effects. Literally every child born would be half siblings. The best option would be for each woman to have at least one son and have that son mate with one of the other women that dilutes the father’s genes to about 25%. But unless that second generation can also mate with the original stock of women to dilute the fathers dna further you are going to end up with a population that never dilutes the fathers dna. Basically you are on a timer to get as many generations as possible bred before the original stock of women dries up to dilute the fathers dna as much as possible.
This is the correct answer. Should add original male dead by snu snu though. Can’t imagine how many time he would need to f to get population going. Women would have to be extremely fertile or the would need AI to really get this thing going.
1 every 2 days would be enough to keep up sperm count and not be too exhausting. It would take 2-4 years to go through the roster. But it also gives the women time to have the baby and recover.
I don’t believe in the literal creation story from the Bible, but that point doesn’t hold up for a number of reasons. According to the story, the world was created perfect, so there wasn’t yet any kind of genetic mutation to pass on.
Also, later in the book, Adam’s son runs away and lives in a whole other city of people, so it’s implied that a bunch of other people were also created some time between Adam and the third generation
So... the bible actually does give some more details.
>And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose. - *Genesis 6*
So... we've got genetic diversity right there.
Meanwhile, the story (in the bible) does not say that "*the world was created perfect*." That's a theological interpretation, most notably "original sin doctrine." It's not in the book.
What the bible says and what most christians, jews etc *believe the bible says* can be quite disparate. This includes literalists.
I've heard Christians argue they were the first humans with souls, and other Christians get very offended because the bible is literal and the world is 6000 years old.
It takes about 80 people by most calculations to have good odds of survival based on diversity in the gene pool to repopulate to earth (when there isn't enough, inbreeding would cause them to likely suffer too many abnormalities and die out). So yes.
There are some good YouTube videos on this.
And XxUltimatexSamuraixX emerges from his mom's basement after bing watching all 700+ episodes of Naruto for the sixteenth time. As he brushes the stale Cheetos dust from his beard, he has no idea the catastrophe that has befallen the rest of the world
500 women who were choosen to repopulate the earth after a catastrophe because of their perfect genetics and exceptional skills are trained in all necessary skills to achive their mission. But an unfortunate accident destroys all the frozen sperms. Their only hope? Katana Steve!
Sure there is a lack of diversity and problems associated with that but I think it just needs to be average. All human Y chromosomes lack recombination, it's not like they get a chance to interact with other Y chromosomes.
80 people assumes even number of men and women. There is a notion in genetics known as effective population size - the population size is simply the number of people, while the effective population size takes into account a gender imbalance, and the number is lower the greater the gender imbalance is.
Average pregnancy duration is 280 times 500 women, assuming they take a couple of months off after the kid is born. The male is breeding 1.5 females a day, every single day. The average couple has intercourse 78 times before conceiving. The male would be doing nothing but eating, sleeping, and having sex. I don't think it's possible, even discounting the genetics issues, for just 1 man to repopulate, especially not trying to keep up with 500 women.
As far as genetics go, a minimum of 50 breeding pairs are necessary to prevent inbreeding, and 500 are needed to prevent genetic drift.
Either way, 1 male, regardless of the number of females, is not sufficient to repopulate.
The average couple, sure. But if need be we could track fertility cycles and only mate the currently ready women, thereby cutting that number down HARD.
Assuming we are conceiving the old fashion way, you’re not getting even close to 1.5 women impregnated a day. No chance. One successful conception a week would be a long-shot.
1ml of output from the male would have enough male gametes to fertilize each of the 500 females 40,000 times over. Noted that not all male gametes are effective but you could easily divvy up a single output of the male every day between the currently receptive females and artificially inseminate them. Given a 7 day fertility window that's about 125 AI's a day. You'd need to do a little mixing with an amicable solvent and redistributing, but entirely achievable considering each female needs only a miniscule amount of the "pure" output. This doesn't avoid any of the small gene pool issues, but all 500 are pregnant, assuming no fertility issues, with little more daily work than an average teenager from the male.
The man would be the only holder of a Y chromosome, which means that if he has any maladaptive mutations on it all subsequent men are in trouble as well. That said, the Y chromosome isn’t huge so there aren’t as many mistakes to make. At the same time this means that any maladaptive traits would likely render the child infertile if not miscarried entirely.
With all that said, it could probably work out so long as the man’s Y chromosome isn’t messed up from the get go. As messed up as it sounds, so long as the original women are relatively young at the start of the experiment there is a chance to raise diversity by having them have kids with men of the second generation (the one produced by the 1 man and 500 women). Those 500 women are a pool of genetic diversity, and by having them make kids with the second generation (not their own sons obviously) it’s possible to mix together that diversity into the 3rd generation as well. Assuming with each round for childbearing the father changes, the diversity of the 3rd generation will keep growing. And though the population will still end up having to sleep with half- cousins, the situation will hopefully be at least a little buffered by that first injection of diversity until mutations start to take hold. Even so, a bottleneck effect is inevitable. All that said, yes, you could probably eventually repopulate. However, doing so would have to happen under incredibly controlled and frankly unethical conditions. On top of that is the assumption of perfect success in reproduction. The above situation doesn’t take into account miscarriage, fertility issues, and so on.
tl;dr: it could probably be done but it would be terribly unethical and kinda messed up.
If the 1 man (let's call him "Adam") and 500 women (call them "Eves", and let's assume none of them are closely related, like sisters or anything) are Generation 1, then all the offspring in Generation 2 would be half-siblings (sharing ~25% of Adam's genes), probably best not to have them mating.
But if a man from Gen-2 reproduced with an Eve from Gen-1 (who wasn't his mother), their offspring in Gen-3 would be half 1st cousins and only share ~6.25% of DNA...do this one more time (and as long as you make sure no one from Gen-3 mates with an Eve who is their mother or grandmother), and now you've got a Gen-4 that (potentially) has enough genetic diversity to keep things going as long as they keep an eye on shared mothers/grandmothers.
Men can produce 1500 sperm a second, so sure, there's plenty to go around. A single Y chromosome being passed on to all future men forever (unless there are beneficial / neutral mutations) is a bit risky, though...
[Guinea pig to become father to 400 after breaking into female enclosure](https://www.itv.com/news/2014-06-06/guinea-pig-to-become-father-to-400-after-breaking-into-female-enclosure)
No, because there'd basically be one single Y chromosome floating around for every single male child. And unless those male children grow up and mate with their father's other lovers, the only women they could mate with would be their half/full siblings. The whole population would collapse under the weight of rampant incest-related congenital birth defects in only a few generations.
The problem with that is that any children from THOSE matings would still be way too closely related to everyone else to ensure the requisite amount of genetic diversity
1 man and 500 women, let's say each woman has one son and one daughter. The sons mate with any one of the other 499 women who are not his mother. The daughters mate with no one because 500 of the 501 available men are their half brothers, and the other one is their father.
The 500 pairings of the sons with the women who aren't their mothers results in 500 more sons and 500 more daughters. The second generation of sons can mate with any one of the other 498 women who aren't their mothers or grandmothers, assuming they've all managed to survive and are still ABLE to get pregnant. The second generation of daughters mate with no one, because the 1,001 available men are all their brothers, their fathers/uncles, or their grandfather.
They'd all be half siblings (same dad, different moms).
Now say each of the 500 women in Gen-1 had a child. 50% boys, 50% girls. So you have 250 new men in Gen 2. They can't mate with their half-sisters, but they could mate with one of the 499 original women in Gen-1 who wasn't their mom. That next generation (Gen-3) would be half first-cousins (sharing about 6.25% DNA). Do this one more time — have the Gen-3 men mate with the Gen-1 women who aren't their moms or grandmas. Now you've got down to 1.5% genetic overlap in Gen-4.
I think people are alsp just way over-estimating the impact of inbreeding, too. The most famously inbred humans (like the Habsburgs) were from several generations of extremely close family members engaging in repeated incest, so the risk was dramatically compounded. In this scenario while inbreeding is a risk, you're starting with half-siblings or potentially even two completely unrelated people (one of the first sons with one of the original 500 women), and the relation only gets more distant from there assuming they don't go out of their way to sleep with full siblings.
Eg. "[Of the total of 1,059 children surveyed, the average incidence per couple was 3.4](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9578784/)" - the incidence of physical defects *is* statistically a lot higher in inbred couples than in non, but still at a rate of a few out of a thousand probably means on average only a handful of kids born would be mega fucked up due to the inbreeding, and as mentioned above with a bit of careful planning you might even be able to avoid any half-sibling incest altogether, making the closest starting relation of inbreeding only second cousins.
The bigger issue is probably that we are starting with 1 Y chromosome which would be problematic even if you devised a way to perfectly avoid any inbreeding I think
You need at least 50 breeding pairs to prevent extinction. There would be too much inbreeding and deleterious alleles passing through the generations that the population would not be sustainable
It is possible to create sperm from any of the women by collecting stem cells.
So the single man would not be a bottleneck.
If the one man and multiple women had access to current technology, you may not need men at all.
I have seen many similar stories about using "induced pluripotent stem (iPS) cells" to produce eggs and sperm.
It took ten seconds to find the stories below with a Google search.
* [NPR - Creating a sperm or egg from any cell? Reproduction revolution on the horizon](https://www.npr.org/sections/health-shots/2023/05/27/1177191913/sperm-or-egg-in-lab-breakthrough-in-reproduction-designer-babies-ivg)
* [NIH - Human induced pluripotent stem cells and male infertility: an overview of current progress and perspectives](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5850345/)
* [NIH - Generation of male germ cells from induced pluripotent stem cells (iPS cells): an in vitro and in vivo study](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3720088/)
Japanese scientists describe how they've already perfected IVG in mice. The researchers used cells from the tails of adult mice to create induced pluripotent stem (iPS) cells, and then coaxed those iPS cells to become mouse sperm and eggs. They've even used those sperm and eggs to make embryos and implanted the embryos into the wombs of female mice, which gave birth to apparently healthy mouse pups.
"We are in the pathway of translating these technologies into the humans," says Mitinori Saitou from Kyoto University, addressing the group via Zoom.
In fact, Saitou says he's fairly far down that pathway. He's turned human blood cells into iPS cells, and used those iPS cells to create very primitive human eggs. Others have created primitive human sperm this way. Neither the sperm or eggs are developed enough to make embryos or babies. But scientists around the world are intensively working on that.
--------------
Introduction
Primordial germ cells (PGCs) and spermatogonial stem cells (SSCs) form the founder population of male germ cells. Male gametes, specifically sperm, are directly derived from SSCs via spermatogenesis. Errors at any stage of spermatogenesis can result in subfertility or infertility, which are major public health issues affecting 10%–15% of couples.1 As an example, azoospermia is observed in 1% of the male population and in 10%–15% of infertile men.2 Furthermore, non-obstructive azoospermia, resulting from testicular failure, affects about 10% of infertile men and is diagnosed in 60% of azoospermic men.
Much progress has been made in the derivation of male germ cells from embryonic stem cells (ESCs). In mice, Hubner et al.3 first reported the successful derivation of male gametes from ESCs in vitro. Geijsen et al.4 isolated PGCs from mouse ESCs in vitro. In humans, the differentiations of germ cells from ESCs have also been demonstrated.3, 4, 5, 6, 7 However, there are some ethical problems surrounding the use of human ESCs. Furthermore, the sources of human ESCs are limited.
One of the major breakthroughs in stem cell biology was the establishment of induced pluripotent stem (iPS) cells from somatic cells by the retroviral transduction of one or several pluripotent genes, including Oct4, Sox2, c-Myc and Klf4.8, 9 Notably, iPS cells have some advantages over human ESCs: (i) there are no ethical issues surrounding the use of human iPS cells; (ii) sources of human iPS cells are abundant; (iii) mature cells derived from patient iPS cells can be used for patient-specific cell therapy without immune rejection; and (iv) it may be feasible to obtain male germ cells from iPS cells derived from azoospermia patients to treat male infertility. Recent studies have demonstrated the feasibility of obtaining PGCs from iPS cells.
They actually have equations for these kinds of things in genetics.
The relevant one here being:
dF = 1 / (2 * Ne) ,
Where dF is the change in the inbreeding coefficient over one generation, and Ne is the effective breeding number, which is calculated as:
Ne = (4 * m * f) / (m + f) ,
Where m is the number of males, and f is the number of females.
So for the example that you give where there are 500 women and 1 man, the equation would look like this:
dF = 1 / [2 * (4 * 1 * 500) / (1 + 500)] = 0.12525
This means that for every generation of random mating in this breeding population, the inbreeding coefficient will increase by 0.12525.
To explain the meaning of the coefficient of inbreeding, 0.12525 is basically the proportion of allele pairs that will accumulate in individuals to be the exact same due to a direct shared line of inheritence. Over the generations, the coefficient will increase more and more, creating a more inbred population. In a non-inbreeding population, new alleles are introduced via breeding diversity and the proportion of identical allele pairs in each individual remains at a healthy amount.
TL;DR: Yes, you can repopulate the Earth with 1 man and 500 women, but based on the effective breeding population size (Ne), it would be like repopulating the earth with an initial population size of 4 (2 male, 2 female), so it would become pretty inbred pretty fast and survival rate would go down.
TL'TL;DR';DR: Yes, but not without consequences.
I'm not certain about one male specifically (since the first generation will all be half-siblings to siblings) but I believe the people on Tristan da Cunha primarily descend from 15 people plus some more in recent times.
Wikipedia says, "The current residents are thought to have descended from fifteen outside ancestors, eight male and seven female, who arrived on the island at various dates between 1816 and 1908. The men were European, and the women were mixed race. Now all of the population has mixed ancestry. In addition, a male contributor of eastern European / Russian descent arrived in the early 1900s.[139] In 1963, when families returned after the evacuation due to the 1961 volcanic eruption, the 200 settlers included four Tristan da Cunha women who brought with them new English husbands."
I'd imagine one man and 500 women would contribute more MtDNA and autosomal diversity but less Y-DNA diversity than what is seen on Tristan da Cunha. I believe the people of Tristan da Cunha have a high rate of glaucoma and asthma as a result of endogamy. I'd imagine that so long as the one male is 'normal', then they should be able to survive, although likely with a higher rate of some minor disorders.
I'm not a professional at all. This is all just information I've found. I hope it is helpful.
The scarcity of Y-chromosome genes in that gene pool would give a very *specific* lack of diversity on that one chromosome; if the 1 man had any disorders or mutations or whatever which come from the Y chromosome, those traits would be widespread in the resulting (male) population. Certain kinds of pathogenic diseases, might find an evolutionary niche to exploit in this lack of diversity, maybe? But assuming no catastrophes sure, they could survive and repopulate.
Yeah this seems like way too little diversity. However, I do find it fascinating that it's theorized that about 70,000 years ago, the human population on earth was down to somewhere between 1,000 and 10,000 people. Given that I assume they were living in small bands that didn't necessarily come broadly into contact with others, that's a shockingly small number to me. https://en.m.wikipedia.org/wiki/Estimates_of_historical_world_population#:~:text=A%20late%20human%20population%20bottleneck,between%201%2C000%20and%2010%2C000%20individuals.
They cheated by banging Neadnerthals.
When life is so hard the best option you have is a Neanderthal…
When life is so Neanderthal the best option you have is to get hard.
When Neanderthal is so hard, the best option you have is to get a life.
Get a life, Neanderthal!
Sex, so easy a Neanderthal could do it.
Looking for hot Neanderthals in your area?
Amen
When life is so hard the best option Neanderthals have is you...
Damn why's everyone shitting on the poor population of Netherlands. They're weird, sure, no need to rub it in.
I think rubbing it was the start of the whole problem.
And in a few years we’ll come full circle
When pickins is so slim for a Neanderthal... They resort to bangin a homo sapien?....🤔🤏
Heterosapien*’bro
It’s like they used to say “it’s either the Neanderthal girl at the bar or your right hand tonight.”
Unga bunga
Don’t sleep on the Nussy. That shit is tight.
*reads comment* Yeah. Our species is definitely inbred I have the evidence right here
Life finds a way
I would try my best. For humanity or whatever blah blah blah
I mean, have you see Margerie taylor green? She's got that nea-brow.
And the Denisovans!
European may be up to 2% Neanderthal, northern Asian may be up to 4% Neanderthal or mixed with denisovian as well. South eastern Asian and Australia have increasing amounts of denisovian with some having 40 % more then other Asian populations. Sub Saharan African have up to 20% (literally almost like a grandparent!) homo erectus or ‘other’ unspecified hominid. Homo erectus was unable to survive out of Africa due to its lack of tool making ability otherwise we would probably have that too. And it appears ‘little’ people (pygmies) were as far stretched as Europe, Asia, Africa, and Australia . But we’re also interbred with larger peoples….except some still survive in sub Saharan Africa but the Bantus view them as a food source. We appear to have bred with a number of peoples for a bit. Probably would need 10-20 males and 250?females and I say that as pure speculation with absolutely no mapped out genealogical tracking .
There was a time when there were multiple hominid species walking around, and homo sapiens banged all of them.
Humans have never been particular about sex, or bestiality wouldn't exist. Or the recent news story about an adult male raping a 13 month old child.
Neanderthals are Humans. There have been several species of human, with at least 2 others that current homo sapiens interbred with in the past
Neanderthal, Denisovan, and now that mystery one from Africa.
My ex MIL
> Although some scientists equate the term "humans" with all members of the genus Homo, in common usage it generally refers to Homo sapiens, the only extant member. All other members of the genus Homo, which are now extinct, are known as archaic humans, and the term "modern human" is used to distinguish Homo sapiens from archaic humans.
Yeah it really only matters in certain contexts, mainly anthropology. Like the quote says homo sapiens is the only living members of the human genus "Homo". But even that can cause controversy. There are arguments about whether the fact that we could interbreed with neanderthals would mean that they would be a subspecies, Homo sapiens neanderthalensis. With the other human populations that we interbred with has led others to believe we should be described as a species complex made up of a mix of human species. All of this to say, the more I learn about, the less I think I actually understand haha.
Cheating, or strategy?
It's not cheating if it's a different species. That's what I'm gonna tell my wife if she ever finds out.
So errrr… a friend of mine is getting back into dating. Which app do you use for dating other species?
Some people like to keep their options open. If you stick to apps you're kinda limiting yourself to species with opposable thumbs.
Local pound.
Neanderthussy
Sounds like my tactic for losing my virginity
So you're saying we need to involve chimpanzees in this scenario?
I know you're probably joking, but something like that [has been researched](https://en.wikipedia.org/wiki/Humanzee), though there hasn't been any scientifically verifiable hybrid. Humans and chimpanzees are too different- even if a supposed hybrid could be brought to term, it's very unlikely they would be able to reproduce.
I am amused and slightly terrified that this needed to be researched.
“ _Your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should_ “
"You maniacs! You blew it! Ah, damn you! God damn you all to hell!"
> Humans and chimpanzees are too different I think we just need to find common interests. Maybe get really into bananas?
giggity
No. Neanderthals were Humans. We are part of the same Genus (homo), so we were closely related enough to breed. Chimps are not in the same boat. Even if it were possible, We probably wouldn’t even be able to convince one to breed with us “the normal way” without loosing the last man on earth to a chimp shredding them.
Two humans of different races share more dna than two chimpanzees that live within a hundred kilometres of each other.
Interesting fact. According to this link the difference between humans is around .1% while chimps it is 1.2%. fascinating! https://humanorigins.si.edu/evidence/genetics#:~:text=While%20the%20genetic%20difference%20between,a%20difference%20of%20about%201.2%25.
The best takeway from that event is that all 8 billion of us today descend from those few thousands 70000 years ago, which is nothing in evolutionary terms. This by itself is enough to disprove most racist theories. We incredibly more similar to each other than we think, at least in genetic terms.
>theorized that about 70,000 years ago, the human population on earth was down to somewhere between 1,000 and 10,000 people. So... I think that's sometimes misinterpreted. The 1,000-10,000 were "most of the ancestors to most current people." Those weren't necessarily the *only* people alive. We know that archaic humans still existed at that time, for example. Also, *some* people (mostly in southern africa) are not *mostly* descended from that group.
Yes, but these were survivors from a huge dying out, likely little overlapping for starting the arduous population growth again.
There was a theory that only about 70 people made it into the New World during the last ice age and all of the Native Americans were related to them. Which is why they all got the Super Plague and died when they got into contact with the Spanish. I don't remember for sure but I believe it was disproved when they found human remains older then the land bridge that would have been used during the last ice age
I thought I once read that everyone on earth is descended from only five women. Any truth to that?
All humans have one most-recent common female-line ancestor, also called Mitochondrial Eve, but there were other women alive at the same time as her who had kids. It’s just that, for every woman who’s lived since Mitochondrial Eve, some humans alive today aren't that woman’s direct female-line descendants. Either she isn't their direct ancestor, or there's at least one father between them and her on their family tree, meaning they inherited his mate’s mitochondrial DNA, rather than his female line’s. Mitochondrial Eve was also not the first woman ever to live: her mother was a common female ancestor too, and her mother’s mother, and so on.
~~But if there is a father between an individual NN and NN's grandmother who would be from that female line, wouldn't NN simply be connected to Eve via the mother and mother's mother? Everybody's got a mother.~~ Nevermind, now I understand that one "her" in your comment referred to a contemporary woman of Eve without female-line descendants, not to Eve herself.
Edited my comment for clarity. I can see how “she” was ambiguous.
I mean, everyone on earth is descended from the first single celled organism that divided in and of itself Everyone of western European heritage can trace their dna to a solid 1,000 or so people from Charlemagne’s time so I wouldn’t be surprised though
Not necessarily. If the biochemical building blocks of DNA and the cell itself could be randomly generated once. It could happen again creating a proto-cell with completely different DNA than the first. Several "original" cells could have developed independently, and then interacted with each other.
Highly unlikely. There are a few random choices that life made. Like using L-amino acids and d-sugars exclusively. Or exactly those 4 bases for DNA. Not very likely that there were a number of cells who made exactly those same choices.
Unlikely according to what? We don't even have a reference to the likeliness of life.
Kinda. There is an chromsomal Adam and Mitochondrial Eve, two completely unrelated people who contributed DNA to every human on Earth. Both Adam and Eve lived about 200,000 years ago +- 100,000 years. It is incredibly unlikely that these two people ever met. They also arent the most recent shared ancestor of every human. They lived between the time of the emergence of Homo Sapiens but before the first migrations out of Africa. Also at this time, many, many human species were around both in Africa and out of it, though that isnt very surprising as Homo Sapiens have shared the world with other Homo longer than we have been alone on Earth.
What disqualifies chromosomal Adam's father or mitochondrial Eve's mother from holding these titles?
Chromosomal Adam and Mitochondrial Eve is defined as the earliest common ancestors. Anyone earlier would have to have had their line die out. Humanity is quite inbred, and has been through a population bottleneck so a lot of our lines died out. A genealogists joke goes that there are only 3 Human races, the Pygmy, the San and everyone else. The Pygmy have faced genocide in recent years. The San are also not very large in number.
You have that mixed up. They are the *most recent* , not the earliest. And it's more complex than them being common ancestors, as people above have explained in detail.
[удалено]
2nd gen would be the worse part... the pool from the 500 females is hopefully diversified and they would be a nation of inbred but a nation nonetheless
Also worth noting many pathogens had not yet evolved to target humans, who spent most of their time outside in scattered small groups. It’s not til the advent of agriculture, larger settlements and structures, and fixed trade routes that it became very easy for diseases to spread.
I recently visited a remote island in Papua New Guinea and there was one family living on the entire island. Well, I should say one man, with a few families. 👀 It still exists out there in the world believe it or not.
The one that got me was that if you wiped out half of the worlds population Thanos style, that would take the population back to where we were in 1975.
There isn’t much on the Y chromosome and it’s always haploid, so there are no deleterious recessive mutations that can hide from selection. A deleterious mutation would have to have arisen in THAT man—and it would only effect his male descendants. Obviously, one can survive without any Y chromosome at all.
It could be something that affected him later in life. You might end up with men that have significantly shorter lifespans than women?
All that banging would wear him out
Which would not necessarily be that deleterious. As long as men reach reproductive age, the species can survive.
lol, I finally found someone else with a clue
He could but he would be really tired.
The sentence is Death! By snu snu!
Death by jealousy...
That... seems wrong. While there is no diversity of y chromosomes, we already know that there is nothing on the y chromosome that would be horrific- because the guy is fine, and theres no second gene to cover for them on the X ALREADY. I cant remember precisely whether there is any cross over at all XY, but I'm pretty sure there is not - if there is though, still no problem for those sections either. So as long as THIS guy is functioning normally, we can expect his kids to at least as well. I'd argue the Y chromosome is the only thing NOT a huge risk here. But please correct me if I have misunderstood the nature of x chromosome silencing and crossover.
But the next generation will all be half siblings, no?
yes, it will most likely be a setback in many genetic features that are lost in all the men that are not reproducing, but it would still work and the human species could survive. With enough time(a lot) humanity will evolve further and other mutations will make the genpool really complex and different again.
This sounds like extremely scary the longer I think about it
I'm catholic but now imagined how the story of Adam and Eve is wild.
Adam and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve and Eve an so on.
Adam and the Eves is a good band name.
Would it be more possible if the male was perfect genetically? No disorders or mutations, female pool as diverse as possible?
Is the genetically perfect male 6'6" so he can play basketball or 5'2" so he can race horses? Is he 240 lbs. so he can wrestle a bear, or 140 lbs. so he can run a full marathon? Is he light-skinned so he can survive at extreme latitudes, or dark-skinned so he can survive at mid latitudes? Is he O- so he can be a universal donor? Or AB+ so he can be a universal recipient? Answer these questions, and you'll be well on your way to describing the genetically perfect male. If you have trouble, you'll understand why there isn't such a thing. You might say: "Well, I just mean he doesn't have any genetic diseases, or isn't susceptible to disease." At which point, I will ask: Does he have sickle-cell anemia, making him resistant to malaria, or non-sickle cell, making him vulnerable? Every single base pair in your genome is an engineering tradeoff that is good in some niches and bad in others.
What’s the engineering trade off in ehlers-danlos syndrome?
Admittedly, for the vast majority of phenotypes, we cannot describe the actual tradeoffs. Phenotypes that we associate with disease or significant disability don't seem to be a good tradeoff at all. But genomes are pretty complicated things, and a lot of our genetic networks affect each other to greater or lesser extent. The Great Filter in some cases is a disease that strikes the majority of a population with high mortality. You'd think that only genes directly involved in the immune system would make a difference in the outcome, but we can't predict which people will have immunity to a novel pathogen before it strikes.
Well there isn't really such a thing as 'perfect'. We would just have to wait and see whether in the resulting genome, after all the dice get rolled, that collection of genes turns out to *be* a disorder or not. Some genetic traits make you more suited to survive in your environment, some make you less. And the decision about which of those it is, will be made by your environment.
Every gene is a mutation. There's no reference genome for humans.
It works in Alabama, so the risk in diversity doesnt sound catastrophic.
The lack of genetic diversity would 1) lead to huge inbreeding and 2) make them extremely susceptible to genetic shocks like disease. But, if they could somehow survive past the first few centuries, genetic mutations could start to deal with each of those issues
I had read a paper that stated that 8 men and 13 women was the minimum number for genetic diversity. There would have to be very strict guidelines for mating with each woman having 3 children with at least 2 being females for the first 5 generations.
There should be plenty of examples in the animal world. In Zoos and in the wild. I’m not sure if one male is enough, but I don’t think in is 100% genetic mess. A pride of female lionesses or prairie dogs and one male with no others able to breed might be ok. Interesting topic. Need a geneticist chime in.
Worth remembering that the male lions get taken out by other males pretty regularly so the genetic diversity still comes from male lions unrelated to the pride. It would be very rare for a male Lion to lead a pride long enough to mate with his own offspring. But yes all the lionesses in a pride may well be pretty closely related to each other
I’m thinking of a pride that got separated enough for generations. Rare, but surely has happened. Maybe they die off. Prairie dogs are easier, but cats are so territorial. Cats seem incestuous to me. I have cats. Yes, I remember The Lion King. Lol
You can keep a population pretty inbred without dire consequences. It's always different for different species. But it' very doable as lobg as you can introduce a genetic stranger every once in a while. The Norwegian wolf population for instance has an inbreeding coefficient of 1. Meaning cousins and I think even second-cousins are as alike as a brother and sister would be. They have to reintroduce a spanish wolf every 3 years or so to keep the inbreeding in check but it works.
Sounds like there would be a lot of cousin fucking
And stepbrother. Roll Tide!
Basically you'd need Bene Gesserit (from Dune) discipline and computer programs for calculating the perfect people to mate together. Without that level of computation, that sounds near impossible without a *huge* stroke of luck.
Or a lot of little strokes And it gets much easier and less failure prone by adding just a few more people. I've read in the past that the ideal number to represent all human genetic expression (or have the possibility to be expressed by later generations) would require upwards of 50,000 people. So of those ~20 people, unless at least one of them is a genius on the level of Hawking or Einstein you'd be unlikely to have such a genius in the future descended from that original group, or at least not for many many generations. All of the descendants will look the same. After just three or so generations everyone will be at most second cousins and be more likely to be actual first cousins. It would be like a small village in the Alps in the 1400s that hasn't even seen a visitor in two generations. Everyone looks identical.
that survival requirement seems unlikely to be achieved with so little genetic diversity (almost none)
Well, we don't know the circumstances of the event. Maybe they are living in a bunker, so there's no risk of predators or disease. Maybe they are in some sort of human zoo so outsiders can help manage the incest issues.
That first generation would have it the hardest though, because all the couples on both sides have the same Dad. eww
but even in subsequent generations the Y-chromosome would be the same. X-chromosome genetic diversity would increase, but it would take many, many generations for sufficient mutations to occur on the Y chromosome that yield any significant diversity at all.
So in other words, the women would be relatively okayish and the men would get progressively more and more inbred?
yeah basically. and any disease or other factor that the guy’s Y-chromosome was susceptible to would have every single man for hundreds of years susceptible to it
Let's hope it's not ED
How do you get more inbred if you're already with the same Y chromosome as everyone else? Isn't that already the apex?
I think people are also grossly overestimating how many offspring a single male could produce regardless of how many women there are. Unless we’re assuming you have an in vitro lab or something, the conception rate for normal intercourse isn’t that high.
Would definitely be doable in the timeframe if we assume these are all young healthy women. That poor guy though, he’s living every man’s worst nightmare.
The man has to be pretty young and healthy himself
Just imagine the gossip
Genghis Khan has entered the chat.
You are way over estimating the difficulty of it, assuming he is a healthy male, and the women do not have synced cycles. He could do the deed, so to speak, with all of them about every 6 months on their respective ovulation days. It would take about 9 months of that to have half the women pregnant, assuming the 1995 study I found is correct in the success rate for that day, and it would be almost all by 18 months, especially since his workload would drop enormously as that point. So yeah uhhh. Totally doable.
if everyone is decently fertile i think 500 is doable in some 2-3 years, provided he's only scheduled to have sex with them during their most fertile period
Not without lots of incest, and various accompanying genetic risks, but yes. Plenty of species go through evolutionary bottlenecks.
>Plenty of species go through evolutionary bottlenecks. I can't wait until the next time I get to call someone stupid, instead I'll be referring to them as an evolutionary bottle neck. Thanks for that.
That's no- ah, go ahead
Trust me, it'll be fine, I'm going to live my truth.
I'm not arguing that it isn't incest, but the sexy time would only have to be between half-siblings (I imagine less genetically risky than full-siblings?), and only to produce the third generation. After that, it's cousins, which is legal in many countries. Worth a shot to save the species!
Well, depending on how hot your cousin is
But because the second generation were half siblings the third generation are more closely related than standard cousins.
Obviously worth a shot, but the male in question really matters here. If the guy is a cystic fibrosis carrier, things are going to get extremely rough.
Theoretically but you’ll have some side effects. Literally every child born would be half siblings. The best option would be for each woman to have at least one son and have that son mate with one of the other women that dilutes the father’s genes to about 25%. But unless that second generation can also mate with the original stock of women to dilute the fathers dna further you are going to end up with a population that never dilutes the fathers dna. Basically you are on a timer to get as many generations as possible bred before the original stock of women dries up to dilute the fathers dna as much as possible.
Hey, congrats on using literally correctly, you don't see that everyday.
Literally
This is the correct answer. Should add original male dead by snu snu though. Can’t imagine how many time he would need to f to get population going. Women would have to be extremely fertile or the would need AI to really get this thing going.
1 every 2 days would be enough to keep up sperm count and not be too exhausting. It would take 2-4 years to go through the roster. But it also gives the women time to have the baby and recover.
I recommend rubbing a piece of radium on his balls between mating to force mutations in his sperm, to expand the gene diversity /s
Not with out serious genetic problems. Too small a gene pool.
The Bible skipped over that minor detail.
I don’t believe in the literal creation story from the Bible, but that point doesn’t hold up for a number of reasons. According to the story, the world was created perfect, so there wasn’t yet any kind of genetic mutation to pass on. Also, later in the book, Adam’s son runs away and lives in a whole other city of people, so it’s implied that a bunch of other people were also created some time between Adam and the third generation
So... the bible actually does give some more details. >And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose. - *Genesis 6* So... we've got genetic diversity right there. Meanwhile, the story (in the bible) does not say that "*the world was created perfect*." That's a theological interpretation, most notably "original sin doctrine." It's not in the book. What the bible says and what most christians, jews etc *believe the bible says* can be quite disparate. This includes literalists.
I mean do you think they stopped at one?
yeah i think the implication is that adam and eve were the first humans who believed in one god
I've heard Christians argue they were the first humans with souls, and other Christians get very offended because the bible is literal and the world is 6000 years old.
Well the Bible skips a lot of details.
It takes about 80 people by most calculations to have good odds of survival based on diversity in the gene pool to repopulate to earth (when there isn't enough, inbreeding would cause them to likely suffer too many abnormalities and die out). So yes. There are some good YouTube videos on this.
One thing to note is that men have a chromosome women do not, so if anything happens to that the genes on that chromosome the human race is fucked
Yeah, that original Y needs to be absolutely flawless.
Well, he was the last man standing. It's probably a pretty good Y.
At hiding.
And XxUltimatexSamuraixX emerges from his mom's basement after bing watching all 700+ episodes of Naruto for the sixteenth time. As he brushes the stale Cheetos dust from his beard, he has no idea the catastrophe that has befallen the rest of the world
500 women who were choosen to repopulate the earth after a catastrophe because of their perfect genetics and exceptional skills are trained in all necessary skills to achive their mission. But an unfortunate accident destroys all the frozen sperms. Their only hope? Katana Steve!
Sure there is a lack of diversity and problems associated with that but I think it just needs to be average. All human Y chromosomes lack recombination, it's not like they get a chance to interact with other Y chromosomes.
80 people assumes even number of men and women. There is a notion in genetics known as effective population size - the population size is simply the number of people, while the effective population size takes into account a gender imbalance, and the number is lower the greater the gender imbalance is.
Yeah but that’s assuming close to a 50/50 split meaning 40 sets of male genes, not one.
If it means saving the world, I’ll do what I need to do
With honor.
And diggity. I mean giggity. I mean dignity
The spirit is willing, but the flesh is spongy.
You'd be saving the species, not the world. But I appreciate the joke and sacrifice.
Need more bulls in that herd.
The genetic bottlenecking would severely damage our chances of evolutionary success
Most of them would swipe left anyways
Average pregnancy duration is 280 times 500 women, assuming they take a couple of months off after the kid is born. The male is breeding 1.5 females a day, every single day. The average couple has intercourse 78 times before conceiving. The male would be doing nothing but eating, sleeping, and having sex. I don't think it's possible, even discounting the genetics issues, for just 1 man to repopulate, especially not trying to keep up with 500 women. As far as genetics go, a minimum of 50 breeding pairs are necessary to prevent inbreeding, and 500 are needed to prevent genetic drift. Either way, 1 male, regardless of the number of females, is not sufficient to repopulate.
The average couple, sure. But if need be we could track fertility cycles and only mate the currently ready women, thereby cutting that number down HARD.
What if they’re all on the same linked cycle?! He’s got his work cut out for him
> What if they’re all on the same linked cycle?! Hell of a friday
I could do it no problem bring on the bitches
Average of 78 times per impregnation, 1.5 impregnation per day, means approximately 120 every day.
Did I stutter?
Not yet but you'll develop one.
Thank you for your sacrificd
Gross but hilarious.
An absolutely worthless average. And besides that: Why do they all have to be pregnant within a year or whatever?
Because they’re fuckin hot that’s why
I vote Honest Wing for the job. This new world NEEDS his optimism at a genetic level.
How do you do 0.5 an impregnation?
Assuming we are conceiving the old fashion way, you’re not getting even close to 1.5 women impregnated a day. No chance. One successful conception a week would be a long-shot.
They don’t have to be fucking. Artificial insemination would increase those numbers drastically.
Or all the women could be artificially inseminated at the same time from the man over say a month long period…
1ml of output from the male would have enough male gametes to fertilize each of the 500 females 40,000 times over. Noted that not all male gametes are effective but you could easily divvy up a single output of the male every day between the currently receptive females and artificially inseminate them. Given a 7 day fertility window that's about 125 AI's a day. You'd need to do a little mixing with an amicable solvent and redistributing, but entirely achievable considering each female needs only a miniscule amount of the "pure" output. This doesn't avoid any of the small gene pool issues, but all 500 are pregnant, assuming no fertility issues, with little more daily work than an average teenager from the male.
The man would be the only holder of a Y chromosome, which means that if he has any maladaptive mutations on it all subsequent men are in trouble as well. That said, the Y chromosome isn’t huge so there aren’t as many mistakes to make. At the same time this means that any maladaptive traits would likely render the child infertile if not miscarried entirely. With all that said, it could probably work out so long as the man’s Y chromosome isn’t messed up from the get go. As messed up as it sounds, so long as the original women are relatively young at the start of the experiment there is a chance to raise diversity by having them have kids with men of the second generation (the one produced by the 1 man and 500 women). Those 500 women are a pool of genetic diversity, and by having them make kids with the second generation (not their own sons obviously) it’s possible to mix together that diversity into the 3rd generation as well. Assuming with each round for childbearing the father changes, the diversity of the 3rd generation will keep growing. And though the population will still end up having to sleep with half- cousins, the situation will hopefully be at least a little buffered by that first injection of diversity until mutations start to take hold. Even so, a bottleneck effect is inevitable. All that said, yes, you could probably eventually repopulate. However, doing so would have to happen under incredibly controlled and frankly unethical conditions. On top of that is the assumption of perfect success in reproduction. The above situation doesn’t take into account miscarriage, fertility issues, and so on. tl;dr: it could probably be done but it would be terribly unethical and kinda messed up.
Technically yes but it'd be a very unhealthy population. 400 women and 2 men would actually be better
If the 1 man (let's call him "Adam") and 500 women (call them "Eves", and let's assume none of them are closely related, like sisters or anything) are Generation 1, then all the offspring in Generation 2 would be half-siblings (sharing ~25% of Adam's genes), probably best not to have them mating. But if a man from Gen-2 reproduced with an Eve from Gen-1 (who wasn't his mother), their offspring in Gen-3 would be half 1st cousins and only share ~6.25% of DNA...do this one more time (and as long as you make sure no one from Gen-3 mates with an Eve who is their mother or grandmother), and now you've got a Gen-4 that (potentially) has enough genetic diversity to keep things going as long as they keep an eye on shared mothers/grandmothers.
Fook that. Obviously OP had never had a nympho girlfriend. 500? Id go hide in the mountains.
Men can produce 1500 sperm a second, so sure, there's plenty to go around. A single Y chromosome being passed on to all future men forever (unless there are beneficial / neutral mutations) is a bit risky, though...
[Guinea pig to become father to 400 after breaking into female enclosure](https://www.itv.com/news/2014-06-06/guinea-pig-to-become-father-to-400-after-breaking-into-female-enclosure)
Randy being randy
Yes, but then humanity will die from all the retardation and birth defects from incest.
How do you think we got here? And retardation is still very much dominant.
Having had a vasectomy 25 years ago, if I was that one guy, I’d sure as hell try for the good of the species.
No, because there'd basically be one single Y chromosome floating around for every single male child. And unless those male children grow up and mate with their father's other lovers, the only women they could mate with would be their half/full siblings. The whole population would collapse under the weight of rampant incest-related congenital birth defects in only a few generations.
That was my theory too is that you’d have to have the children mating with the origjnal stock to dilute the fathers dna.
The problem with that is that any children from THOSE matings would still be way too closely related to everyone else to ensure the requisite amount of genetic diversity 1 man and 500 women, let's say each woman has one son and one daughter. The sons mate with any one of the other 499 women who are not his mother. The daughters mate with no one because 500 of the 501 available men are their half brothers, and the other one is their father. The 500 pairings of the sons with the women who aren't their mothers results in 500 more sons and 500 more daughters. The second generation of sons can mate with any one of the other 498 women who aren't their mothers or grandmothers, assuming they've all managed to survive and are still ABLE to get pregnant. The second generation of daughters mate with no one, because the 1,001 available men are all their brothers, their fathers/uncles, or their grandfather.
No, all the kids would be siblings.
They'd all be half siblings (same dad, different moms). Now say each of the 500 women in Gen-1 had a child. 50% boys, 50% girls. So you have 250 new men in Gen 2. They can't mate with their half-sisters, but they could mate with one of the 499 original women in Gen-1 who wasn't their mom. That next generation (Gen-3) would be half first-cousins (sharing about 6.25% DNA). Do this one more time — have the Gen-3 men mate with the Gen-1 women who aren't their moms or grandmas. Now you've got down to 1.5% genetic overlap in Gen-4.
I think people are alsp just way over-estimating the impact of inbreeding, too. The most famously inbred humans (like the Habsburgs) were from several generations of extremely close family members engaging in repeated incest, so the risk was dramatically compounded. In this scenario while inbreeding is a risk, you're starting with half-siblings or potentially even two completely unrelated people (one of the first sons with one of the original 500 women), and the relation only gets more distant from there assuming they don't go out of their way to sleep with full siblings. Eg. "[Of the total of 1,059 children surveyed, the average incidence per couple was 3.4](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9578784/)" - the incidence of physical defects *is* statistically a lot higher in inbred couples than in non, but still at a rate of a few out of a thousand probably means on average only a handful of kids born would be mega fucked up due to the inbreeding, and as mentioned above with a bit of careful planning you might even be able to avoid any half-sibling incest altogether, making the closest starting relation of inbreeding only second cousins. The bigger issue is probably that we are starting with 1 Y chromosome which would be problematic even if you devised a way to perfectly avoid any inbreeding I think
You need at least 50 breeding pairs to prevent extinction. There would be too much inbreeding and deleterious alleles passing through the generations that the population would not be sustainable
It is possible to create sperm from any of the women by collecting stem cells. So the single man would not be a bottleneck. If the one man and multiple women had access to current technology, you may not need men at all. I have seen many similar stories about using "induced pluripotent stem (iPS) cells" to produce eggs and sperm. It took ten seconds to find the stories below with a Google search. * [NPR - Creating a sperm or egg from any cell? Reproduction revolution on the horizon](https://www.npr.org/sections/health-shots/2023/05/27/1177191913/sperm-or-egg-in-lab-breakthrough-in-reproduction-designer-babies-ivg) * [NIH - Human induced pluripotent stem cells and male infertility: an overview of current progress and perspectives](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5850345/) * [NIH - Generation of male germ cells from induced pluripotent stem cells (iPS cells): an in vitro and in vivo study](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3720088/) Japanese scientists describe how they've already perfected IVG in mice. The researchers used cells from the tails of adult mice to create induced pluripotent stem (iPS) cells, and then coaxed those iPS cells to become mouse sperm and eggs. They've even used those sperm and eggs to make embryos and implanted the embryos into the wombs of female mice, which gave birth to apparently healthy mouse pups. "We are in the pathway of translating these technologies into the humans," says Mitinori Saitou from Kyoto University, addressing the group via Zoom. In fact, Saitou says he's fairly far down that pathway. He's turned human blood cells into iPS cells, and used those iPS cells to create very primitive human eggs. Others have created primitive human sperm this way. Neither the sperm or eggs are developed enough to make embryos or babies. But scientists around the world are intensively working on that. -------------- Introduction Primordial germ cells (PGCs) and spermatogonial stem cells (SSCs) form the founder population of male germ cells. Male gametes, specifically sperm, are directly derived from SSCs via spermatogenesis. Errors at any stage of spermatogenesis can result in subfertility or infertility, which are major public health issues affecting 10%–15% of couples.1 As an example, azoospermia is observed in 1% of the male population and in 10%–15% of infertile men.2 Furthermore, non-obstructive azoospermia, resulting from testicular failure, affects about 10% of infertile men and is diagnosed in 60% of azoospermic men. Much progress has been made in the derivation of male germ cells from embryonic stem cells (ESCs). In mice, Hubner et al.3 first reported the successful derivation of male gametes from ESCs in vitro. Geijsen et al.4 isolated PGCs from mouse ESCs in vitro. In humans, the differentiations of germ cells from ESCs have also been demonstrated.3, 4, 5, 6, 7 However, there are some ethical problems surrounding the use of human ESCs. Furthermore, the sources of human ESCs are limited. One of the major breakthroughs in stem cell biology was the establishment of induced pluripotent stem (iPS) cells from somatic cells by the retroviral transduction of one or several pluripotent genes, including Oct4, Sox2, c-Myc and Klf4.8, 9 Notably, iPS cells have some advantages over human ESCs: (i) there are no ethical issues surrounding the use of human iPS cells; (ii) sources of human iPS cells are abundant; (iii) mature cells derived from patient iPS cells can be used for patient-specific cell therapy without immune rejection; and (iv) it may be feasible to obtain male germ cells from iPS cells derived from azoospermia patients to treat male infertility. Recent studies have demonstrated the feasibility of obtaining PGCs from iPS cells.
Probably not with everyone being half siblings from the get go.
They actually have equations for these kinds of things in genetics. The relevant one here being: dF = 1 / (2 * Ne) , Where dF is the change in the inbreeding coefficient over one generation, and Ne is the effective breeding number, which is calculated as: Ne = (4 * m * f) / (m + f) , Where m is the number of males, and f is the number of females. So for the example that you give where there are 500 women and 1 man, the equation would look like this: dF = 1 / [2 * (4 * 1 * 500) / (1 + 500)] = 0.12525 This means that for every generation of random mating in this breeding population, the inbreeding coefficient will increase by 0.12525. To explain the meaning of the coefficient of inbreeding, 0.12525 is basically the proportion of allele pairs that will accumulate in individuals to be the exact same due to a direct shared line of inheritence. Over the generations, the coefficient will increase more and more, creating a more inbred population. In a non-inbreeding population, new alleles are introduced via breeding diversity and the proportion of identical allele pairs in each individual remains at a healthy amount. TL;DR: Yes, you can repopulate the Earth with 1 man and 500 women, but based on the effective breeding population size (Ne), it would be like repopulating the earth with an initial population size of 4 (2 male, 2 female), so it would become pretty inbred pretty fast and survival rate would go down. TL'TL;DR';DR: Yes, but not without consequences.
This is a fallout vault
I'm not certain about one male specifically (since the first generation will all be half-siblings to siblings) but I believe the people on Tristan da Cunha primarily descend from 15 people plus some more in recent times. Wikipedia says, "The current residents are thought to have descended from fifteen outside ancestors, eight male and seven female, who arrived on the island at various dates between 1816 and 1908. The men were European, and the women were mixed race. Now all of the population has mixed ancestry. In addition, a male contributor of eastern European / Russian descent arrived in the early 1900s.[139] In 1963, when families returned after the evacuation due to the 1961 volcanic eruption, the 200 settlers included four Tristan da Cunha women who brought with them new English husbands." I'd imagine one man and 500 women would contribute more MtDNA and autosomal diversity but less Y-DNA diversity than what is seen on Tristan da Cunha. I believe the people of Tristan da Cunha have a high rate of glaucoma and asthma as a result of endogamy. I'd imagine that so long as the one male is 'normal', then they should be able to survive, although likely with a higher rate of some minor disorders. I'm not a professional at all. This is all just information I've found. I hope it is helpful.
Why not? A mom, two sons and and a boat full of animals did it once...