Y Chromosomal Adam and Mitochondrial Eve: Polygenism and probabilistic considerations

[Paleophyte]

If I'm wrong, pls explain why with reasons.

OK. For a start it's hilarious that you icluded "probabilistic considerations" in the title given that mtDNA Eve and Y-chromosome Adam are entirely statistical effects. There were probably no fewer than 10,000 people alive at the times. Yes, times, plural. Their existence was separated by a few tens of thousands of years. Anything that you may have heard about population bottlenecks was written by pop-sci writers whose grasp of the science was almost as weak as yours. mtDNA Eve and Y-chromosome Adam are statistical artifacts of genetic drift and tools that allow you to follow only a single lineage.

Here's an easy way to visualize it. Draw a family tree of only your ancestors back to your great-great grandparents. There ought to be 16 people at the furthest generation. Now trace the exclusively matrilineal and patrilineal lines. This is what mtDNA and Y-chromosome analysis does. Clearly you're related to all 16 of your great-great grandparents but you can only trace your mother's mother's mother's mother using mtDNA and your father's father's father's father using the Y-chromosome. The techniques are simply blind to the rest of the population. You can only trace two out of sixteen of your ancestors.

Now simply repeat. For your matrilineal great-great grandmother trace her matrilineal great-great grandmother. And similarly for your patrilineal great great grandfather. And now you can only see 2 individuals out of 256 (give or take).

Repeat again and you're down to 2 out of 4096 ancestors. And all this winnowing has taken just 12 generations. A little math will show you that the soonest possible emergence of 2 distinct individuals from the whole of the human population will happen some time in the 12th to 10th century AD, depending on a couple of assumptions. That would be a wee bit inconvenient for all the Abrahamic religions, having Adam and Eve born centuries after their prophets lived and died. But, that's just a mathematical minimum. Nature is nowhere near that tidy with generations being an arbitrary construct that had vertical mingling and populations inbreeding (mostly at very large scales so it wasn't monster-begetting or disgusting, I'm talking 8th cousins and better here) and isolating from one another to slow the process up a lot more.

And thus you have a pair of tools that, when you look far enough into the past, reveals only two ancestors from whom we are all descended. Missing the billions of other from whom we are also all descended.

The fun part is that mtDNA Eve and Y-chromosome Adam aren't simply statistical artifacts, they're also artificial ones. Their identities are entirely dependant on the populations that you choose. Include the Neanderthals and Denisovans and you have to go a much, much longer way back into prehistory to find a completely different "Adam" and "Eve".

Misunderstanding science to prove mythology. What a farce.