If Adam and Eve produce a large population before the interbreeding starts, then we can guarrantee that we all get soem of their DNA, if they are far enough back in time. My estimate right now is that if they were 200 kya, there would have to be one pure-blooded Adam-decendent mixing with 4 non-Adam descendents for this to work. We would all have about 20% of our genome from Adam in that case.
Is such a large population (1/5 of the total human population at the time, if I understand it) credible before mixing? After all, Cain found a wife immediately.
In this model I think Cain’s would have been his sister. There would likely have to be some population growth first, I imagine.
How would the Adamites have avoided noticing all the other people in the area, once leaving the garden? Or do you suppose they would have been consciously preferring to inbreed? Hey, doesn’t this also have severe population genetic effects on allele frequency distributions and such?
Perhaps they did not. Perhaps grew to a larger population size in the local area without mixing then mixed and spread.
This loosely matches somewhat the population boom of the agricultural revolution, but would have been a long time ago in the past.
Let’s remember you have them growing to be 1/5 of the total human population before leaving the area. That would seem to be a local population in the millions, all before encountering other humans.
I’m not sure that is accurate. We know that Sapiens didn’t interbreed that much with other species. If sapiens arise as through a localized mixing event that then spreads with attenuated interbreeding, it might only require 10s or 100s of individuals. The precise size of the bottleneck would be constrained by TMRxA in the sapien specific lineages.
That seems like quite a different scenario from what you were talking about before. If there’s limited interbreeding, won’t Adam contribute more like 90% of the genome? We have his descendants filling the world, occasionally mating with a neandertal or denisovan. What you were proposing before was H. sapiens outside the garden as well as inside, with Adam’s descendants merging into the population. Further, this doesn’t match even a modified out of Africa scenario.
It is different.
I’m led be the evidence. This seems to be the implication of a TMR10A=180kya. Perhaps 1 or 2 lineages are from Neanderthal or Denisovan, but not much more than this. Maybe 3 tops? Rather than litigate that, it might be better to check directly. Whatever the case, I don’t think we are down to 2.
This is more important for me to understand. Why does this not work with out of africa? In this case, Adam and Eve would be at the rise of Sapiens, in Africa.
Oh, I thought the garden had to be in the Middle East somewhere. If it’s in sub-Saharan Africa, don’t a number of the early Genesis stories have problems? Come to think of it, I guess there are serious problems with any story that puts Adam and Eve much before the origins of herding and agriculture. Adam’s curse, Cain and Abel, founding cities, and all that are just out. Are you cool with that?
The meaning of “this” is unclear. Could you clarify? I don’t understand what the current scenario is. Are you proposing a bottleneck in Africa down to 10 or 100 individuals, into which the descendants of A&E integrate? This all needs to be articulated more clearly.
We are not talking about me, so it doesn’t really matter if I am cool with it.
Yes, you either have to ditch the agricultural setting of Genesis, or infer a lost history of agriculture. This is a problem. You also do have to move it to Africa.
Reasons to Believe (@AJRoberts), who would go this path in their thought experiment, would say that there was a lost history of agriculture, and that upper Africa is “close enough” to the Middle East.
The “this” is just what I described earlier:
10 alleles is 5 people, so I’m seeing my numbers are off here. Sorry, it is late at night. So if 4 alleles comes from Adam and Eve, then 6 would have to come from others. So that would be a mixing ratio of 1:1.5. I’m sure we can derive time dependent scale that tells us what percentage of our ancestry would have to come from a place other than Adam and Eve this way.
Whoah there cowboy!
The only reason to tolerate such an option is if the audience doing so is dropping a Global Flood in order to do so.
If the audience in question insists on a Global Flood, suggesting the Cain married an unmentioned sister is just a cunning way to avoid the topic of the pre-Adamite human population!
You will need to take into account the spread of Homo-Sapiens within Africa. Africa is a huge continent and there were millions of the genus Homo in Africa for about two million years. Homo Erectus left Africa and populated outside of Africa in the millions. Neanderthals and Denosvians evolved outside of Africa. Homo Sapians, if you place them evolving as a species in Africa 300,000 years ago, had a lot of company in Africa with other species of the genus Homo. The diversity of African Homo Sapiens is much larger than the diversity of Homo Sapien outside of Africa.
Bottom line: If your place Adam in Africa around 300,000 years ago at the beings of Homo Sapiens, you have to have about 200,000 years of diversification WITHIN Africa to match up with the DNA data.
I’m not sure that is correct. What is the evidential basis of this claim?
What would the linkage disequilibrium data look like in this model, and how does it compare to modern populations?
Population genetics isn’t my strong suit, so please feel free to criticize the question if need be. From my limited understanding, it takes time for recombination to separate alleles that are close to each other in the genome which makes this data a good source for looking at bottlenecks (again, if I understand it correctly). Would it be correct to say that this 20% that came from Adam and Even in your model could potentially have stronger linkage disequilibrium than the rest of the genome?
Linkage disequilibrium is included in the ancestral recombination graph. It is not obvious where there would be conflict with the data.
It don’t think people marrying their sisters has any basis in fact. We don’t see that in mammals with mating occurring between siblings. And I would think that culturally it would not have been wide spread even for Homo Erectus 2 million years ago.