Genetic Population

[Jprime]

Does anyone here know how many humans are necessary for an inbreeding-free, stable genetic population?

[GuyFromOH]

From what i can remember, I think it's somewhere around 100. It's been brought up before in a lot of space-colonizing scifi shows, including ST:TNG, and I think even in a James Bond movie. I think the more the better, but with 100 (probably 96) by the time you are mating with relatives, they are so far away on the family tree that the genetic pool doesn't start getting shallow.

[Madeleine]

I remember reading that thirty of each sex was the bare minimum. I can't remember if there were any stipulations such as needing the sixty to be from diverse ethnic groups or needing them all to be above-average healthwise.

[ShadowMaat]

Well, after a while the ethnic groups would sort of blend out, wouldn't they? And you'd get a sort of homogenized skin tone... with shadings to either end of the scale, of course. But that would probably be a big "eventually" and assuming that folks didn't do something stupid like try and stick ONLY to their ethnic group...

[Vala]

I heard 500 would be good for a diverse population

[Jprime]

Ok thanks guys!

[Madeleine]

It would help for them to be of different ethnic groups, although not so much because of skn colour. There are genetic characteristics common to some parts of the world and not to others; blood types, build and resistance to certain diseases for instance. It would be good to have a variety of those localised traits within the group in case any turn out to have survival benefits for the population in their (presumably) new habitat.

[5aret]

I think you need about 500 for a stable population and they have to be of
the same blood type.

[SGSlugger]

The same blood type? That's a little strict, don't you think?

If you were starting a colony or something, you would probably have to have a wide diversity of people.

[ShadowMaat]

I should think they'd need to be of DIFFERENT blood types. What if someone needed a transfusion or something?? You can't give an A-neg person B-pos blood. People of different blood types marry and have kids all the time. It's good for genetic diversity and all. Having all of one blood type would, I think, weaken the race. And it's taking genetic purity just a little TOO far. ;)

[5aret]

I was just repeating what I have heard somewhere. Know that I think about it, a colony would have to be made up of diffrent blood types.

[Jprime]

a good idea would be to bring a larger number of O blood type because they can give transfusions to ANYONE (with iron based human blood.

[ShadowMaat]

a good idea would be to bring a larger number of O blood type because they can give transfusions to ANYONE (with iron based human blood.
O-negative, yes. They're universal donors. O-positive is another story. I think... ;)

I'm o-neg, myself, but I don't weigh enough to donate blood. Stupid rules.

[Nolamom]

I'd say gain a little weight, but then, being small and fiesty suits you! I'm A negative and the hubster if something positive. The only problem is with the Rh factor (neg/pos). When you have children and the mother is negative, if the baby is postive the mother builds up antibodies to the child. No problem with the first, but if a second is born who is also negative, it can lead to huge problems (up to and including a complete tranfusion for the infant)

[Vala]

I think you need about 500 for a stable population and they have to be of
the same blood type.
That was on sliders and that was only because the dude needed the strict blood sampels for his dissorder.

[5aret]

That was on sliders and that was only because the dude needed the strict blood sampels for his dissorder.

What is "for his dissorder" thing? I said that I was repeating what I heard somewhere. You did not have to be mean about it.
;) ;)

[ShadowMaat]

I didn't see it as "mean", I saw it as a statement of fact. Granted, you may have heard it somewhere else, but it also showed up in an ep of Sliders. The character in question had a blood disorder and in order to control/fix it, he needed people of a certain blood type. Hence all the people of that colony or whatever being "required" to have the same type of blood.

Haven't seen the ep, myself, but that's what I can extrapolate based on Vala's post.

Generally speaking, though, I think that a mix of blood types, traits, skin tones, etc would make the colony stronger than if, for example, everyone was blonde-haired and blue-eyed and had A-positive blood.

[Shipperahoy]

O-negative, yes. They're universal donors. O-positive is another story. I think... ;)

I'm o-neg, myself, but I don't weigh enough to donate blood. Stupid rules.

I'm O-neg myself but the weight requirements aren't a problem. You must be tiny. :p There are all these commercials on the radio here about the blood banks needing O-neg blood. I guess it's time to give again.

[Madeleine]

Arrrrgh! Needles in my arm!

Sorry, I had a flashback. I don't like giving blood. Even if it does get me the morning off work.

[ShadowMaat]

I'm O-neg myself but the weight requirements aren't a problem. You must be tiny. :p
I'm small but feisty. ;) And I fight dirty...

[Jprime]

A+ here! Man how big do you need to be to give blood? Is there an age limit?

[ShadowMaat]

A+ here! Man how big do you need to be to give blood? Is there an age limit?
I would guess you have to be at least 18 and you have to be in excellent health and weigh more than 110 pounds.

*grumble* Two outta three...

[Jprime]

So your one of those cute little exitable people one sees on the bus getting irritated at the annoying kids sitting next to them?

[ShadowMaat]

So your one of those cute little exitable people one sees on the bus getting irritated at the annoying kids sitting next to them?
No, I'm one of the small, quiet ones you never even see until it's too late. :D

[Jprime]

Lol every day I almost sit on one of the regulars. Her legs barely reach halfway to the floor and shes virtually invisible. :D

[nugglebugget]

I had afriend once who was into figuring out different "genetic" stuff.He calculated ,going back to the approximate time of "Noah's Ark & the flood",taking into account an estimate of how many generations since,he figured that everybody on the earth is at least a 40th cousin to each other[based on our collective ancestry being from Noah & his family,that is].

Btw,I'm o-negative ,too.My husband is A-positive,All 4 of my kids had positive RH & I had to get those Rhogam shots after each one ....ouch!

[5aret]

Sorry about what I said. I thought you said I had a disorder. I read it to fast.
Sorry about that. :cool: ;)

[Lostinmyownvoid]

So your one of those cute little exitable people one sees on the bus getting irritated at the annoying kids sitting next to them?
I'm the kind of person who goes to the parents of annoying children and say "Now I know why snakes eat thier young".

For genetic diversity you need about 250 persons. 500 is to many and you want your civilization to go as many generations as possible before it breaks 1000. They should only be allowed two children 1 girl and 1 boy. That way you have atleast 36 years before your population could safely reach 1000. Also for those first 36 years you need psuedo-communism to micromanage and optimize time usage.

[Jprime]

Yes I have adjusted my my preliminary calculations. Thank you.

[5aret]

Hmm.. Cool. Why would not want your colony to reach 1000??

[Lostinmyownvoid]

Think of it this way
Population/Years passed
250/0
500/18
1000/36

1000 is alot of people and after that the population increase is quite steep. You want as much time as possible to prepare your agriculture and housing before that happens.