Faz Rana swings and misses on evolution

If that’s a modified GAE, then genetic Adam is also a modified GAE, and the term loses all meaning. GAE relies on there being an evolved population of Homo sapiens, not just of some other species of Homo.

That’s hardly the major problem with the idea. More broadly, making H. sapiens look in all respects like a product of evolution, within Homo, within Hominini, within Homininae, within Hominidae, is the worst sort of omphalism, and interbreeding with other Homo species is the least of it. Of course it does require a bottleneck in the non-Denisovan, non-Neandertal portions of your genome (which would be all of the genome for what are paradoxically the most genetically diverse populations).


Yes you are right. It isn’t a GAE, but it relies on some of the same insight.

That is just the otherside of the same objection. I don’t disagree with you.


If there was intermixing, effective population size doesn’t tell you much about the size of the Homo sapiens population within that larger group of ancestors.

Beg to differ, as one can distinguish Neandertal/Denisovan sequences from H. sapiens sequences. Excluding the former from the sample and considering only the latter tells you about the size of the ancestral H. sapiens population.

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To be clear here Homo sapiens is just a placeholder for only a roughly corresponding group of AE’s descendents.

If we position that, for example, AE were a couple in northern Africa 200kya ago, who’s offspring quickly interbreed with surrounding hominids, perhaps mixing in a 2 to 1 ratio, for thousands of years…well I’m not sure how the evidence rules this out.

That’s the opposite of clear.

That isn’t the scenario. That would end up with H. sapiens being dominated by the non-A&E genomes. It’s pretty much the straight GAE scenario, nothing to do with what RTB propose.

So now it is nothing to do with the GAE? Depending on the details there could be a middle ground between the two.

How do you get that from “It’s pretty much the straight GAE scenario”?

I mean it was “nothing to do with GAE” to being straight GAE. I’m saying there is a continuum. The precise detail and constraints from the evidence I cannot give you. At least not yet…

I have no clue how to parse that sentence.

But there is not. Your inability to construct a reasonable middle-ground scenario shows that. We see quite a small amount of hybridization between H. sapiens and two other Homo species preserved in the genomes of various non-African groups. You can’t turn that into GAE melded into RTB’s genetic Adam no matter how hard you try.

So here is a more productive question @John_Harshman, what do you think the TMR4A date for the Homo sapiens specific lineage is? This would exclude all non Homo sapiens DNA, so it would be less than 500 kya.

Sorry, I’ve forgotten what TMR4A means. I’m also not sure what the point is that you’re trying to make. Could you explain?

Time to Most Recent 4 Alleles. That is how we would figure out how much interbreeding is required. If not 4 alleles, what about 8 or 10? This gives us a way to quantify how much interbreeding is required.

Still not getting what you’re trying to do here. How much interbreeding of what with what? I think you need to express yourself in more than a couple of sentences. As far as I can tell we’re trying to distinguish a) the scenario in which a created couple of H. sapiens and their offspring freely interbreed with an evolved population of H. sapiens from b) the scenario in which the created sole couple of H. sapiens and their offspring interbreed with separate species of Homo. Is that what you’re trying do do here? And if so, how? If not, what are you doing?

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How about this. I will explain more soon. I just can’t tonight. Is that okay? Not a dodge. Just reality.