But even this approach is not really very relevant. The 4th great grandparent assessment is looking at the INDIVIDUAL-SPECIFIC genetics… rather than the POPULATION-AVERAGES.
IF the 1.5% was based on mitochondrial genetics… that would mean 3 Neanderthal females for every 197 homo sapiens females!
Hmmm… that would be 1 for every 66 sapiens or so.
1 < 2p < 4gp < 8gp < 16gp < 32gp < 64gp …hmmm…
Hey, @John_Dalton… I think you make a good point!!!
Its more like a percentage of a percentage… Humans a and neanderthals genomes are fairly similar… I have heard of a similarity to the tune of 99%. 1% is supposed to be uniquely human DNA/Uniquely Neanderthal DNA. In some populations, 1-4% of the “uniquely neanderthal DNA” is is found in human beings (i.e. its 4% of 1%… increase in similarity from 99% to 99.04%).
Hmm, that makes sense. But, if that percentage of the dissimilar DNA is uniquely Neanderthal, that still suggests a roughly-calculated Neanderthal influence of around that 1-4%, right? That somehow in some sense there was that amount of Neanderthal admixture (and not .04%)?
not necessarily… its just the most parsimonius explanation. Alternate scenarios seem possible. For example
Humans and neanderthals are supposed to have a common ancestor 500000 years ago when they diverged.If its not a clean break and interbreeding happened among various proto neanderthal populations/human populations at some point before they completely split into different species (say 300000 years ago) it possible to have a similar result without any interbreeding between fully fledged human and neanderthal populations…
verifying what really happened is not very easy.
I just want to add that nobody assumes a large scale hybridisation between Humans and neanderthals. Even those who propose a recent hybridization event ( approx 50,000 years ago) (which seems to be a strongly held view) conclude that it was rare… and most of the off spring were sterile. In such a scenario, a less 2% rate of interbreeding is mentioned.
Another genealogically interesting fact is that our great great great grandparents contributed approximately 3% to our DNA… (we have 32 grand parents… hence the 3% percent figure)
However, i don’t think that is what Patrick is talking about when he talks about the neanderthal GA.
Yes, it wasn’t a one time chance meeting. Sapiens and Neanderthals shared all of Eurasia for perhaps as long as 150,000 years from about 180,000 years ago until Neanderthals went extinct (or were subsumed into Sapian populations) about 30,000 years ago. There must have been a lot of intermingling going on as human males will mate with just about any thing. As for the Neanderthal genes in our genomes, realize that our genomes contain the genes from a very small number of ancestors. So there is a lot of intermixing that is completely hidden from study current people’s genome. That is why the study of ancient genomes is so important.
So, was the story my grandmother told me when I was a child not literally true? How can that be? I trusted my grandmother to be inspired and truthful. How could she get the story so wrong. She was born in 1908, had no formal education in paleontology and genomics, but she really wanted to tell us (her grandchildren) a story on how to live a good life. I really want to believe her story so I will try to match anything I can find in the sciences with her story, sort of like what Hugh Ross does with the latest finding in Cosmoslogy.
Perhaps we could agree that our friend @Patrick does, at times, appear to exhibit some “Neandertalish” traits? : )
I know I have friends who’ve told me I’d make “a great ape…” Cheers!
But did her story end up to be correct, despite the fact that she could not have known anything about genomics, for instance? Heck, it really is remarkable that, generation after generation, the story remained the same!!
So happy for you that, so many years later, great x 20 grandmother was vindicated by science in the form of ancestry.com!!
Honestly, I think we’ve witnessed the evolution of @patrick over the last several months. He is a better man, or maybe he is showing us a better side of himself. What ever the case it, the evolution has been fun to watch.