View Full Version : Sufficient humans to repopulate?

07-03-03, 12:02 AM
I was wondering if 4 males and 4 females is sufficient
to repopulate the human race. If not that what is
the minimum?

In terms of repopulating is 6 males and 2 females
equivalent to 4 males and 4 females?

EDIT: fix female

07-03-03, 12:35 AM
1. why would you want to?
2. good god are you going to put 4 males with only 1 poor lil ol female? poor thing!

07-03-03, 01:20 AM
Sorry I meant 4 females. I'm creating a scifi that needs to be plausible.

07-03-03, 07:58 AM
I'd say a lot more than 4 and 4, and more women than men. Maybe 8 Males and 20 females to keep the grandkids from being "slow" after inbreeding.

07-03-03, 08:58 AM
I remember 30 was the minimum for a genetically stable population, below that and your going to end up with freaks. It was things like this that made the Icelanders the way they are today… did I say that out loud?

cthulhus slave
07-05-03, 01:41 PM
id say 25 females and 10 males might be suficiant. ideally they should be as genetically divrse as possible. try geting mice (they breed relitivly fast) and have sevral big cages w/ difrent numbers of mail and female and see wich cage after a few years has only retards. mice and men are similar.

actually that wouldnt hellp at all but arnt mice just so cute!

~ ~

07-06-03, 01:20 AM
If you let the mice produce as many offspring as they possibly could in a competitive enviroment I think they might do better. The retards would be outcompeted by any nonretarded siblings.

Just because the resulting mice might be nonretarded dosnt mean they would in any other way resemble their ancestors. Most new breeds of mice were originally developed through inbreeding.

07-06-03, 08:21 PM
a single pregnant female could be enough

there is a lot of data out there asking and trying to answer this question with a variety of different organisms

may i suggest going here , choosing pubmed, and search databases using some search term like "founding population" or "minimum viable population"

07-06-03, 09:15 PM
:rolleyes: obviously genetics isn't either.

tell me how a single pregnant female can repopulate a entire species? Don’t tell me: her son going to mate with her or no to twin a male and female? Unfortunately this kind of inbreeding would most likely result in still-born or infertile children after 2-3 generations.

07-06-03, 10:40 PM
The buildup of "bad genes" (usually recessive) is what causes problems for inbread animals. These can be removed by natural selection.

If she has 12 offspring every 3 months (being a mouse) and each of her offspring has 12 offspring every 3 months you will have a sizeable breeding pool. Many will suffer nasty side-effects from the inbreeding but some will most likly not be carrying any debilitating recessive genes. They will breed far more than those afflicted with genetic disorders and live to do it again and again. Thus the species continues.

Human women can't breed that fast though.

07-06-03, 11:19 PM
genetic problems depend on the load. if the recessives aren't present, or can be weeded out, then no problem.

Clockwood: actually, Templeton wrote a paper based on data for Speke's gazelle (breed once per year, i.e. less frequent than human female) and reported the load was eliminated.

So, it could be done with humans. Which is my point.

If you're gonna argue with me, you ought to do the literature search first.

07-07-03, 02:37 AM
Originally posted by paulsamuel

If you're gonna argue with me, you ought to do the literature search first.

wow, dude. you really are full of yourself. you should realize that most of us in this forum are biologists as well. you're not that rare a breed my friend. rein in that ego before someone loses an eye.

07-07-03, 02:52 AM
if you're a biologist, then you should know that knowledge is based on empirical structure or logical structure or (usually) a combination of both. things aren't true just becasue somone says they are.

stick to the topic instead of attacking the response

07-07-03, 03:05 AM
Your the last person to stick to a topic paulsamuel.

Why don't you explain how a single pregnant female can make a legitimate repopulation without resulting in major genetic and phenotypic changes from the original population?

07-07-03, 03:13 AM
i already did

you refuse to read! because you already know it all i presume

07-07-03, 03:27 AM
I'm sorry I though I already posted a reply to that, mut be the insomina getting to me.

No I don’t believe you could ever find humans without any recessive genotypes, in the inbreeding the recessive would build and the resulting offspring (if fertile) would be very genetically distinct from the original species, if you don’t believe me I take this from a seminar by a ecologist that calmed he was having the same problem with a group of moths he is try to perceiver here in Minnesota.

07-07-03, 03:34 AM
you are my bitch!

finding a human without recessives is irrelevant.

you continue to refuse to learn. you just need one with no or few deleterious recessives.

your contention is that there's no one in all human future and history that would not have deleterious recessves.

i'm saying it's possible, and if this individual is female and pregnant, then that's all you need, and not even that extreme. some deleterious recessives are allowable if they can be weeded out.

07-07-03, 03:41 AM
but very unlikely, hence a recommendation of 30 was made is some nature article several years ago about the genetics of low populations (I can remember when and the title).

If only you were/are a women then I would be like "More mistress, more!"

good night! and sleep dreaming of me ;)

07-07-03, 03:49 AM
well. do i detect humility?

yes, unlikely but possible, hence my first post.

dude, do you have too much time on your hands? (re: making that smiley face S&M scene), but i have to admit, it made me laugh.

07-07-03, 04:00 AM
If you have the whip, some wicked spiked leather bondage equipment, and breast then sure humility or what ever you want to call it. In reality though humility is when I tell you out right I'm wrong... since that has not happen yet don't get your hopes up.

you like the smilies do you here some more:

*Fetus falls over dead form lack of sleep.*

07-07-03, 04:12 AM
Originally posted by WellCookedFetus
In reality though humility is when I stop countering your claims, which I haven’t yet so don’t get your hopes up.

I'm looking forward to tomorrow then when you counter his claims...

maybe hell will freeze over...

i think it is obvious that a single pregnant female could repopulate a species, because it has in all probability happened for other species in the past. Why wouldn't it be possible for humans?

07-07-03, 04:22 AM
I just did!, did you not read my post above?

but very unlikely, hence a recommendation of 30 was made is some nature article several years ago about the genetics of low populations (I can remember when and the title).

sure it could happen, at about the same chance as me winning the lottery. You need a gene pool with some variety to start with to make the chances of success likely.

and now I can't sleep, fuck off!

07-07-03, 04:29 AM
you didn't counter my claims.

given the possibility, and time, it's inevitable

07-07-03, 04:34 AM
How much time do you have with one viable female? Speciation did not happen like that it happens from small population becoming genetically separated and under the strain of different environmental factors, it still requires a breeding population.

Dr Lou Natic
07-07-03, 05:04 AM
Originally posted by spuriousmonkey
i think it is obvious that a single pregnant female could repopulate a species, because it has in all probability happened for other species in the past. Why wouldn't it be possible for humans?
But usually when that happens the species starts to evolve into a new one. At least from what I've seen. I find it very interesting, its seems very convenient, if the numbers are that low somethings not right and walla, they evolve.
I tried to make a thread about this subject but nobody cared:(

07-07-03, 07:30 AM
maybe the human species is already evolving...

07-07-03, 08:21 AM
ya at our population we are going to evolve at the same rate jellyfish.

or is that just something that came to your mind from 3001? ;)

07-07-03, 09:00 AM
Originally posted by WellCookedFetus
ya at our population we are going to evolve at the same rate jellyfish.

it is difficult to predict selective pressure that will drive evolution of a species. There is no reason to assume that repopulating a species from a single, or a few individuals will seriously change the essence of the human species. We are already quite good opportunists. If we do not need to change our lifestyle, then there might not be any different selective pressures than right now, with a population of billions.

07-07-03, 09:38 AM
I love how you can repeat what I said but with much greater detail.

07-07-03, 10:00 AM

07-07-03, 12:48 PM
do your homework! read!

use search terms like 'founder population'. 'minimum viable population'

hawaii is a great place to start.

it could happen, and it probably has in some species, perhaps even humans.

but you refuse to learn.

don't you know that knowing everything is the surest obstacle to ever learning anything

07-07-03, 03:53 PM
I did do my homework that strait from a General Biology textbook written in the last 3 years. It requires a founding population and never mentions a situation of just one individual begetting a how species.

07-07-03, 04:02 PM
A second example is Speke's gazelle. The entire North American herd was derived from 1 male 3 females. Obviously, from very first generation, all individuals breed in captivity were related (all had to have single male founder as a common ancestor). Hence, pedigree inbreeding unavoidable. Thus, founder and bottleneck effects promote rapid increases in pedigree inbreeding.

almost one.

source: link (

07-07-03, 04:16 PM
Yes almost, but was the species recovered or is this a new species now, see the question was how many do you need to repopulate the species without result in something that is genetically and phenotypically distinct even incompatible, from the original.

07-07-03, 04:33 PM

07-07-03, 04:47 PM
And with just one how would that work? Unless it hermaphroditic?
Even so the amount of inbreeding would be so intense that very few offspring would survive and if any do they did would most likely be genetically distinct for the original.

07-07-03, 09:41 PM
why will you not learn?

why will you not think?

you amaze me?

you read a general biology book and you think you know everything.

you really are a fool.

one pregnant female could be sufficient to repopulate.

07-07-03, 09:47 PM
like I said it could be but its very unlikely, way don't you ever read what I said? Does your ego problem blind you?

07-08-03, 12:43 AM
Originally posted by paulsamuel

stick to the topic instead of attacking the response

i felt it was necessary to mention because all i see coming from you is insults. i have yet to find a post in this forum written by you that does not include an ad hominem. that certainly does make a good argument nor does it form the basis of knowledge as you claim to know all about. before you yell at others for getting off topic, check to see how on topic you are yourself.

continue gentlemen/gentlewomen

07-08-03, 12:53 AM
so 1 pregnant female, huh?

sure she'd be able to repopulate but i'm not sure it's a great idea. the founder of hawaiian drosophila may have had success but they also reproduce, hence evolve, significantly faster.

07-08-03, 12:55 AM
unlikely + geologic time = inevitability

learn from that!

07-08-03, 01:21 AM
I guess it might help if we had a single pregnant female carrying identical twins.

EDIT: I meant of course identical twins of different sexes, if that is possible.

07-08-03, 01:22 AM
was that a balanced equation? i hope you have references to back it up and review articles tracing the mathmatical work leading up to this equation. also, show me a complete proof. can i plug this into a graphic imaging system?

07-08-03, 01:30 AM
I don't have to, because I don't know anything about this subject. I'm a layman here. It is just my guess.

07-08-03, 01:34 AM
you're too ignorant to understand the concept, but this is one of the basic tenets of evolutionary biology and the foundation of geology and humankind's first steps into modern science, i.e. the first inklings of the age of the earth

07-08-03, 02:16 AM
Originally posted by WellCookedFetus
:rolleyes: obviously genetics isn't either.

tell me how a single pregnant female can repopulate a entire species? Don’t tell me: her son going to mate with her or no to twin a male and female? Unfortunately this kind of inbreeding would most likely result in still-born or infertile children after 2-3 generations.

the thing is of course, that scientists make inbred lines all the time. And they thrive in the lab. The lines do not perish after 2-3 generations. They thrive for decades and decades. Would something similar then be possible for humans? Is there any theoretical hindrance to this notion, or is it just because we were taught that inbreeding is bad and will weaken the spine, similar to masturbating.
If I summarize the matter then Paulsamual has good reason to believe that it is possible to create a stable population through inbreeding and this notion hasn't really been refuted anywhere here.

And we may continue to attack his 'aggresive' style in this case, but this aggressive stance might be induced by other people's shameless intrusion into his subject, without acknowledging that they could be wrong, or even contemplating that they might be wrong.

But I am not really an expert on this subject and I find it difficult to judge, but I do know that I had similar experiences in this forum and that it is difficult to remain 'cool' in these cases. Especially because most sciforumers can't really know who they can trust or not. And they will just trust the person they have seen around most, or like.

Is this about being right. Not really, it is about intrusion. Someone comes into you backyard and starts throwing in the windows of your house.

anyway...i said what I wanted to say...

07-08-03, 08:48 AM
So I take it 1 female is enough. What would cause enbreeding kids to not survive? Is it some DNA that's mutated but we require later in life which is the source of the problem? I just can't comprehen why two similar DNA can't repopulate and diverge over time.

07-08-03, 09:01 AM
The problem is that everyone carries recessive traits (aka Gene that don't work right or well and are covered over by dominate ones) when inbreeding there is a much higher chance making children with homozygous recessive genotype, there are many recessives that are lethal or greatly debilitating but in a population with a good gene pool the chances of making homozygous recessive in one of those lethal traits is very low.

07-08-03, 03:21 PM
you are right! it can happen although there are potential problems.

recessive traits are not necessarily deleterious! wellcooked is wrong when he defines recessive traits as 'genes that don't work well.'

the problem with inbreeding is called inbreeding depression, which is a decrease in fecundity due to inbreeding (it merely means a female is less reproductively successful over her lifetime due solely to inbreeding). the reason for inbreeding depression is expression of deleterious recessive traits. this happens at a low rate. the rate and the amount of inbreeding depression is entirely dependent on the genetic load of the population. But with a small AND inbred population, chances are increased that, merely by chance recombination of traits, that a whole breeding season is unsuccessful, and over time, the population can go extinct.

it is NOT that inbred children don't survive, most survive fine, but even one less successful offspring, due solely to inbreeding, is measurable and called inbreeding depression.

ergo, wellcooked is WRONG when he says that it can't happen

07-08-03, 05:07 PM
They don't work in competition to dominate traits. Again I did not say it can't happen I said it was unlikely to happen. paulsamuel has a ego problem Specialist, you see his life is not good enough for him so he has to come here to push people around, he will interpret any vague or with exception statement as wrong so that he can show-off, he will also not respect any neutral answer such as mine where I say it unlikely to be successful he interprets that as it will never happen so that he can hammer me on his own Straw Man fallacy… it pathetic really.

07-08-03, 08:05 PM
there is no strawman. there's a real target, you!

when you mislead, misinform or lie, i will expose you.

you said, "They don't work in competition to dominate traits."

that's, literally, nonsense.

stop whining about being picked on, use your intellect, stop spewing crap and misleading people who really want to learn something, dumbass!

07-08-03, 09:10 PM
Recessive traits are any traits that only function when an associated dominant trait is not present. Red hair is a recessive trait. In fact it popped up several times in human history due to moderate amounts of inbreeding.

07-08-03, 10:16 PM

Do you know what a strawmen is? Lets clarify that first:

Person A has position X.
Person B presents position Y (which is a distorted version of X).
Person B attacks position Y.
Therefore X is false/incorrect/flawed.

You have been claiming that I’m wrong for saying a single pregnant female cannot beget a species, I never said that.

In reality the recessive trait never works or does not works as a efficiently as a dominate this is way the trait get cover over. White and red rose is a good example: a white rose has 2 recessive versions of the red rose pigment gene or gene related in that pigments production, when a recessive and dominate are together in a heterozygous pair the Rose appears pinks because its only producing half the pigment a double dominate homozygous would. There are also stages of recessives and dominates and many exceptions to the dominate/recessive rule.

07-09-03, 12:27 AM
you don't even know what recessive means.

recessive genes are not expressed except in the homozygous state

the rose example is partial dominance or co-dominance

again you're misinforming, misleading and/or outright lying

you really ought to know what you're talking about before you open your mouth, dumbass

07-09-03, 12:31 AM
recessive genes are not expressed except in the homozygous state

Did I not already state that, oh wait that right you said that was wrong, strange seeing you back down on that.

again you don't take vague or a lack of terminology on my part as being anyway correct which is a lie on yours.

07-09-03, 12:46 AM
no you didn't say that.

you lied again.

07-09-03, 12:59 AM
I said: "They don't work in competition to dominate traits"

you said: "recessive genes are not expressed except in the homozygous state "
which means that in a heterozygous paring by your logic they are not expressed which means that the recessive trait does not appear in the presence of the dominate, perhaps my laymen terms are to beyond you, which is weird since most people have problems with words with many syllables not the other way around. Face it your nit-picking on anything I say to try to prove me wrong.

07-09-03, 01:37 AM
he already did several times.

07-09-03, 01:42 AM

I would expect more from you, you don't find his behavior wrong or offensive in anyway?

07-09-03, 01:46 AM
no, he is right...he might not be very nice, but I am not so nice either.

but you never know when to quit either and say that maybe you are wrong. I also find that offensive as you may have noticed in the past.

nobody is perfect here.

07-09-03, 02:07 AM
I have said I was wrong on many thing before, but I am never saying I am wrong to a jerk that calls me a “dumbass” every other thread, second I have not been wrong on this subject yet: I have stated that it is unlikely for a single pregnant female to repopulate a species without either die off all together from inbreeding or result in a new variant or even species from gross genetypical and phenotypical changes… so far no one has argued against me on these points only attack me with ad hominems and strawmen on things I never said.

07-09-03, 02:09 AM
we do it all the time in the lab. Why wouldn't it be theoretically possible for humans?

07-09-03, 02:13 AM
from a single pregnant female?

07-09-03, 02:30 AM
yes....for some species it is really easy...

for instance C. elegans.

pick one up, put it on a new plate...and there you have your new colony.

07-09-03, 02:43 AM
We are talking about a hermaphroditic nematode here, I already made exception for hermaphroditic, especially ones that can self fertilize.

07-09-03, 02:48 AM
take one pregant fruitfly...or one mouse...doesn't matter. Big litter mates simplify having partners for the next generation I guess.

07-09-03, 02:54 AM
and do you have sources on this? I would like to see.

07-09-03, 02:56 AM
uh...just take one pregant fuitfly and keep it separated...uh???

i thought it was common practice?

07-09-03, 03:00 AM
Really never heard of it, but then again I have not done much with fruit flies (aside from a single graded mutagen experiment)

07-09-03, 03:04 AM
i haven't either...maybe I was just thinking it...probably...

anyway...maybe someone else knows..

07-09-03, 03:15 AM
Dam it to hell if its going to be paulsamuel! I'll ask Dr. Kvaal ( here at SCSU about it, he might know, hes a real professor and he does not have the maturity of a snobbish 6 year old.

07-09-03, 04:14 AM
This would seem to support WellCookedFetus's position on HUMAN
repopulation of a species. Low birth rate, usually only one offspring
produced at a time.

A multilocus stochastic model is developed to simulate the dynamics of mutational load in small populations of various sizes. Old mutations sampled from a large ancestral population at mutation-selection balance and new mutations arising each generation are considered jointly, using biologically plausible lethal and deleterious mutation parameters. The results show that inbreeding depression and the number of lethal equivalents due to partially recessive mutations can be partly purged from the population by inbreeding, and that this purging mainly involves lethals or detrimentals of large effect. However, fitness decreases continuously with inbreeding, due to increased fixation and homozygosity of mildly deleterious mutants, resulting in extinctions of very small populations with low reproductive rates.

07-09-03, 04:43 AM
don't think so

07-09-03, 04:49 AM

It would be nice if you could post a reference to dam all those that might disbelieve.

07-09-03, 06:22 AM
still...there seems to be no theoretical hindrance to the notion of one pregnant female repopulation the human species. People have been presenting the worst case scenarios of inbreeding, but not all scenarios have to be worst case.

hence my position is still the same.

07-09-03, 10:30 AM
Sure, I will try, but it is a LONG link.

07-09-03, 10:42 AM
Also, click on the Related Articles thread on the page. There are

07-09-03, 01:30 PM
Originally posted by paulsamuel
you're too ignorant to understand the concept

whew! flew right over your head. perhaps if you removed your lips from your own ass, jesting at your expense wouldn't escape you so easily.

07-09-03, 02:37 PM
stop lying!!!! you are so slimey, you give me the heebie jeebies, you ought to have gone into politics.

no one disbelieves effects of inbreeding depression, or that deleterious recessives result in inbreeding depression in small and inbred populations. i explained it to you! i have spoken and met with both Dr.'s Charlesworth (have you? have you even heard of them??!!). we work on similar topics in the broadest sense (they are more mathematically oriented and use plant systems in their models while i work on real data and from animals) i.e. conservation genetics, and i know that they would agree to my answer to the original question while at the same time knowing the problems associated with inbreeding. this abstract, agrees with me, not with you.

07-09-03, 02:49 PM
good job on your literature research!

i wish wellcookedfetus would do some research, but he already knows everything

pubmed at ncbi is a great resource. did you use search terms I provided or did you pick one yourself? and what was it?

thanks, Paul

07-09-03, 03:11 PM
Paulsamuel: "I am your God all must bow down before me, or else I won’t like that and you will suffer horribly! HAHAHAHahahaha, cough”

Spuriousmonkey: “All hail are new god!!!”

WellCookedFetus: “I am not respecting a egomaniac that claims to be a god!”

2inquisitive: “God?!?! Has a freaking asshole! Lets insult him the same way he’s insulting us!”

… and after this: the thread maturity drops by 2 year every post.

07-09-03, 03:18 PM

let me get this strait even when the article presents evidence against you, it actually support your claims because the authors (you assure us) would make your claims an exception?

07-09-03, 03:28 PM
i think the point might have been that the 'evidence' was not actually discussing this scenario but a different one. Hence it maybe shouldn't be used as evidence against the notion that one pregnant female could repopulate a species.

or not...

07-09-03, 03:29 PM
it appears you didn't read the article, again.

It does require some genetics background, which, it appears, you do not have.

no where does the article disagree with me. As i stated, it agrees with me, and with all the background theory i have provided in this thread.

07-09-03, 03:32 PM
Sorry, I am not into insults, I just thought the literature was
relevant to this thread.
Thanks, Paul, I did use my own search terms but I can't remember
exactly what they were. My memory is not as good as it used
to be.

07-09-03, 03:36 PM
no problemo.

keep up the good work.

07-09-03, 03:41 PM

Well yes all I have done was read the abstract, even so all you have stated is that the article agrees with you simply because the authors would agree with you as you claim, and possible that there work is not relevant, because of it use of plants and simulated models, again this is no proof of anything on your part only hearsay. If you would mine put up better evidence on your part that actually from the article then we might also have proof that you actually read it as well.

we work on similar topics in the broadest sense (they are more mathematically oriented and use plant systems in their models while i work on real data and from animals) i.e. conservation genetics, and i know that they would agree to my answer to the original question while at the same time knowing the problems associated with inbreeding. this abstract, agrees with me, not with you.

07-09-03, 03:48 PM
i will say this again, and i cannot stress the importance of this enough, READ!

when you read you learn, you find more references to the topic, you'll find that the topic is not discreet and will link intellectually to a plethora of other topics.

a good rule of thumb is (and i know this is difficult, so don't beat yourself up over it if you can't do it continuously) one journal article per day. if this is too much, try one per working day (5 per week)

07-09-03, 04:03 PM

That’s strange you obviously did not read what I said, let me state it again: there is no proof you read it either, until then you have no valid argument unless you attack the article it self or present other articles. You really have a problem in presenting arguments: failing to have a proper premises or valid claims, constant use of fallacies. When you speak like a professor I will respect you like the one you claim to be, until then you nothing but a jerk.

I do have a subscription to Nature and SA you know, and I don’t pay for them to lay on my desktop either.

07-09-03, 04:25 PM
Ok, I'm going to pretend to be moderator here

let us try to figure out how we can resolve this dispute. We have seen some references, but with my layman knowledge I would venture to guess that this wouldn't so far exclude the possibility of a single pregnant female population founder.

So...for both parties. Can we summarize our main points and possibly give a reference to support our position. And if you still have time left, maybe argue why this reference supports your position and not the other.

Idle Mind
07-10-03, 12:01 AM
You should be a mod spurious...

As for this thread, I am disgusted. Why are you people (paulsamuel and WellCooked, I'm looking in your direction) bickering like children? Don't answer that, it is meant rhetorically.

Anyways, the original question posed by Specialist, lest you've forgotten was this:

I was wondering if 4 males and 4 females is sufficient
to repopulate the human race. If not that what is
the minimum?
The answer, disregarding likelihood as it was not stated in the original question, is a single pregnant female. That's it! Conversation over. If his (or her) question were more specific, and perhaps asked what the minimum number for establishing a genetically stable human population with the least likelihood of failure, then I could see maybe having a disagreement. But that is not the case.

We are all here to learn, and it is incredibly difficult to take you two seriously when each thread is filled with childish insinuations and outright insults.

Grow up.

07-10-03, 03:19 AM
thanks Idle Mind!!

In the words of Mugato (of Zoolander), I thought I was taking crazy pills here!

07-10-03, 12:08 PM
My bad