# Re forced inbreeding of people in a confined area. Would they survive or not? **URL:** \ **Category:** Factual Questions\ **Created:** [August 14, 2010, 4:21am UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217 "2010-08-14T04:21:40Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Chessic\_Sense](https://avatars.discourse-cdn.com/v4/letter/c/7c8e57/32.png) [@Chessic\_Sense](https://boards.straightdope.com/u/Chessic_Sense)\ **Post date:** [August 15, 2010, 5:39am UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/21 "2010-08-15T05:39:10Z")
> [@Freudian\_Slit](#): > > Remove their culls? I’m a little confused. I thought to cull meant to reduce a group’s numbers. So what is a cull? If only there was a book somewhere that was nothing but a list of short descriptions of what words meant… ---
**Author:** ![Hazle\_Weatherfield](https://avatars.discourse-cdn.com/v4/letter/h/e9bcb4/32.png) [@Hazle\_Weatherfield](https://boards.straightdope.com/u/Hazle_Weatherfield)\ **Post date:** [August 15, 2010, 8:11am UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/22 "2010-08-15T08:11:18Z")
For those who take the bible literally: how do you explain the successful population/re-population of the earth via Adam, Eve, Cain and Abel and Noah’s offspring. Yikes! ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [August 15, 2010, 8:37am UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/23 "2010-08-15T08:37:36Z")
> [@Hazle\_Weatherfield](#): > > For those who take the bible literally: how do you explain the successful population/re-population of the earth via Adam, Eve, Cain and Abel and Noah’s offspring. Yikes! Pretty easily, actually. All humans alive today have been traced to a common male and female ancestor. The problem is that they probably did not live at the same time. ---
**Author:** ![Sablicious](https://avatars.discourse-cdn.com/v4/letter/s/bbce88/32.png) [@Sablicious](https://boards.straightdope.com/u/Sablicious)\ **Post date:** [August 15, 2010, 1:03pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/24 "2010-08-15T13:03:57Z")
Hasn’t this experiment been conducted already, below the Mason-Dixon line[?](http://instantrimshot.com/) 😕 ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 5:02pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/25 "2010-08-15T17:02:35Z")
> [@BigT](#): > > > [@Hazle\_Weatherfield](#): > > > > For those who take the bible literally: how do you explain the successful population/re-population of the earth via Adam, Eve, Cain and Abel and Noah’s offspring. Yikes! > > Pretty easily, actually. All humans alive today have been traced to a common male and female ancestor. The problem is that they probably did not live at the same time. That’s a common misunderstanding of Y-chromosome Adam and mitochondrial Eve. Neither was your only male or female ancestor from that time. “Adam” was your male line only ancestor and “Eve” was your female line only ancestor. You had other male ancestors who lived at the time of “Adam”, but at some point you are descendant from them through a female. Adam is the unbroken male line ancestor. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [August 15, 2010, 7:05pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/26 "2010-08-15T19:05:31Z")
> [@John\_Mace](#): > > > [@BigT](#): > > > > Pretty easily, actually. All humans alive today have been traced to a common male and female ancestor. The problem is that they probably did not live at the same time. > > That’s a common misunderstanding of Y-chromosome Adam and mitochondrial Eve. > > Neither was your only male or female ancestor from that time. “Adam” was your male line only ancestor and “Eve” was your female line only ancestor. > > You had other male ancestors who lived at the time of “Adam”, but at some point you are descendant from them through a female. Adam is the unbroken male line ancestor. Could you make this example more concrete? I’m having a bit of trouble understanding what you’re saying here. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 7:19pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/27 "2010-08-15T19:19:05Z")
> [@astro](#): > > > [@John\_Mace](#): > > > > That’s a common misunderstanding of Y-chromosome Adam and mitochondrial Eve. > > > > Neither was your only male or female ancestor from that time. “Adam” was your male line only ancestor and “Eve” was your female line only ancestor. > > > > You had other male ancestors who lived at the time of “Adam”, but at some point you are descendant from them through a female. Adam is the unbroken male line ancestor. > > Could you make this example more concrete? I’m having a bit of trouble understanding what you’re saying here. The Biblical Adam and Eve were the ancestors of all humans, and they were the only male and female ancestor we had, at the time. Y-chromosome Adam wasn’t your only male ancestor at the time. He was your father’s, father’s, father’s… father. But suppose Adam had a contemporary. Let’s call him Ralph. Ralph might be your ancestor, too, but only through the female line at some point. So, between you and Adam, there are only men, but between you and Ralph there was at least one woman. The reason for this being so is that we get our Y chromosomes only from our fathers and our mtDNA only from our mothers. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [August 15, 2010, 7:22pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/28 "2010-08-15T19:22:06Z")
> [@astro](#): > > Could you make this example more concrete? I’m having a bit of trouble understanding what you’re saying here. In both cases we are looking at only part of the genome. You may have inherited your X-chromosome from a male who was alive at time x. The X-chromosome is inherited as a unit, and obviously only through the male line. However, you may have inherited genes on your other 45 chromosomes (22 paired autosomes plus X) from other males who were alive at the same time, and these could have descended through the female line. Likewise for mitochondrial Eve, who only provided the mitochondrial genome. Other females alive at the time (and males) would have contributed to your nuclear genes. ---
**Author:** ![runcible\_spoon](https://avatars.discourse-cdn.com/v4/letter/r/9fc29f/32.png) [@runcible\_spoon](https://boards.straightdope.com/u/runcible_spoon)\ **Post date:** [August 15, 2010, 7:27pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/29 "2010-08-15T19:27:52Z")
‘Adam’ is your father’s father’s father’s father’s… father’s father. There were other males alive at the same time who were (for example) your father’s father’s father’s… mother’s father, but there’s a female between you and them, so they’re not ‘Adam’. ETA: Aaaaaand, preview next time. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 7:28pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/30 "2010-08-15T19:28:55Z")
> [@Colibri](#): > > > [@astro](#): > > > > Could you make this example more concrete? I’m having a bit of trouble understanding what you’re saying here. > > In both cases we are looking at only part of the genome. You may have inherited your X-chromosome from a male who was alive at time x. The X-chromosome is inherited as a unit, and obviously only through the male line. I’m sure you meant “Y-chromosome” in that last sentence. 🙂 ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 7:33pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/31 "2010-08-15T19:33:22Z")
> [@Elendil\_s\_Heir](#): > > Maybe a dumb question: Could cloning and/or gene splicing be used to remove bad genes and to artificially genetically “diversify” a population? Cloning wouldn’t, since it is, by definition, the creation of an identical twin. Gene splicing could theoretically be used, but without a reference population, you wouldn’t know exactly how to diversify the population. Do you want different hair color, different heights, or what? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [August 15, 2010, 8:01pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/32 "2010-08-15T20:01:44Z")
> [@Colibri](#): > > > [@astro](#): > > > > Could you make this example more concrete? I’m having a bit of trouble understanding what you’re saying here. > > In both cases we are looking at only part of the genome. You may have inherited your X-chromosome from a male who was alive at time x. The X-chromosome is inherited as a unit, and obviously only through the male line. > > However, you may have inherited genes on your other 45 chromosomes (22 paired autosomes plus X) from other males who were alive at the same time, and these could have descended through the female line. > > Likewise for mitochondrial Eve, who only provided the mitochondrial genome. Other females alive at the time (and males) would have contributed to your nuclear genes. Sorry for being slow here, but here’s what my layman’s ears hear - Biologists say - There is this “Adam” and “Eve” hypothesis that means our genome shows we (Homo sap.) all came from one original woman. OK - so I’m thinking that the mutation that made us homo sap. came from one woman we are all descended from. Her kids had kids and carried it forward etc. Cool! Biologists say - No that’s wrong, she wasn’t the homo sap “mutation”. it’s simply evident in our genome, that a _part_ of the human genome can be traced back to one (1) individual female. OK - So I’m thinking if she wasn’t the Ur mutation what reason is there that the proto-human population and it’s descendants all came (in part) from this one woman as the homo sap. “Eve”. What choked the population down to one individual? Starvation, catastrophe… what? Biologists say- Sigh - No, No, No! Only a little snippet of the genome comes from one person. There are lots of other parts that came from other people alive at that time. OK- So I’m not really understanding the relevance of the “Eve” thing at this point. Biologists say- Now you must die. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 8:15pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/33 "2010-08-15T20:15:00Z")
To get to Eve, you work backwards. You look at lots of mtDNA all around the world and see how different it is. You make some assumptions about how often mutations arise, and then you figure out how long it took for those mutations to result in what we see today. That turned out to be about 150k years ago. For Adam, it was much later-- about 60-90k years ago IIRC. But it doesn’t have to have anything to do with being _H. sapiens_. Theoretically, mtDNA Eve could have been an _H. erectus_ female. She’s just the earliest female (measring time backwards from today) that we are all related to through the female line. Obviously, we are related to her mother as well through the female line. And her grandmother, etc. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [August 15, 2010, 8:40pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/34 "2010-08-15T20:40:42Z")
Actually, the “Eve thing” is more of a curiosity than a significant scientific finding. It tends to muddle things a bit as too many people think she’s our most recent common ancestor. In fact, as we’ve seen in this and other threads, our most recent common ancestor is a lot more recent than Eve. But that common ancestor wouldn’t be a strictly male or female line only ancestor. ---
**Author:** ![j666](https://avatars.discourse-cdn.com/v4/letter/j/9de0a6/32.png) [@j666](https://boards.straightdope.com/u/j666)\ **Post date:** [August 15, 2010, 10:09pm UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/35 "2010-08-15T22:09:32Z")
> [@md2000](#): > > The problem with a sibling pair is that about 50% of their genes are identical, so a defective recessive gene has a good chance of “pairing up” with itself. Do the math - the first generation, 25% will be defective offspring, 50% carriers. With respect, that assumes “defective” traits are cause by a single gene, that environment has no influence how or whether the gene is expressed, and that the trait is absolutely defective, rather than the trait will be beneficial in some environments. That’s the kind of example we might be given in school, because it’s easy to explain and genetic problems like that are the easiest to identify. Assume a trait related to two genes, one dominant, one recessive, and one apparently triggered by an environmental factor, and the math gets a bit more complicated. The greater risk to the population is more practical; if the first birth is difficult, the population would die out in one generation. ---
**Author:** ![robardin](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@robardin](https://boards.straightdope.com/u/robardin)\ **Post date:** [August 16, 2010, 12:04am UTC](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217/36 "2010-08-16T00:04:28Z")
> [@astro](#): > > Sorry for being slow here, but here’s what my layman’s ears hear - > > Biologists say - There is this “Adam” and “Eve” hypothesis that means our genome shows we (Homo sap.) all came from one original woman. … > > OK- So I’m not really understanding the relevance of the “Eve” thing at this point. The problem is with the cutesy name of “Y-Chromosomal Adam” and “Mitochondrial Eve”, which suggest to people the Biblical story of Adam and Eve who are the progenitors of all humanity from the top down. The fact is that Y-Adam and mt-Eve are statistical facts in a genetic progression, due to [pedigree collapse](http://www.straightdope.com/columns/read/412/2-4-8-16-how-can-you-always-have-more-ancestors-as-you-go-back-in-time). There is always a “most recent common ancestor” between ANY two creatures on Earth; the only question is how long ago that was. That estimation is based on assumptions of an observed constant average rate of random genetic mutation. That’s how (most) scientists estimate things like the most recent common ancestor between humans and chimps or gorillas, except that we’re talking about people from other people “in the worst case”. And based on the fact that mitochondria come only from the mother while Y-chromosomes for men come only from the father, we can separately estimate the Most Recent Common Male Ancestor Of All Men and Most Recent Female Ancestor Of All Women. What was surprising about Y-Adam and mt-Eve, and why it became big news earlier this decade, is how recent they project to be in human history after enough global genetic data was collected and analyzed to give any confidence to the projection. They’re not “Adam and Eve” in the sense of a breeding pair that Began It All, rather they’re labels for a convergent data point in a backwards looking time series (two separate ones, in fact). That’s also NOT saying that all other women who were alive at the time of mt-Eve have had zero genetic impact on modern humanity. They also have sons, and pass genes on to them, who can then also have daughters who receive genes from their fathers (and thus from those women in question). It’s just the specific female-line genetic marker that being looked at - mitochondria - that’s being followed; mitochondria is not the sole genetic story of a woman, any more than the Y-chromosome marker they’re follwing for Y-Adam is the sole genetic contribution from a man. [Previous page](https://boards.straightdope.com/t/re-forced-inbreeding-of-people-in-a-confined-area-would-they-survive-or-not/550217.md?page=1)