In France you can find Neanderthals’ tools in your garden, everywhere. A small population is indeed hard to believe.https://t.co/b2I2WbLUsL
— David Enard (@DavidEnard) September 18, 2017
The above tweet is in response to a article which reports on the finding past month in PNAS, Early history of Neanderthals and Denisovans. It’s open access, you should read it. I don’t think I’ve reviewed it because I haven’t dug through the supplements. To be frank this is a paper where you pretty much have to read the supplements because they’re introducing a somewhat different model here than is the norm.
I talked to Alan Rogers at SMBE about this paper. Broadly, I think there might be something to it, and it’s because of what David says above. It is simply hard to imagine that Neanderthals could be extremely successful with such low genetic diversity as we see, and spread so thin. Now, the Quanta Magazine tries to emphasize that the effective population is not the true census population, but I wish it would have explained it more clearly. Basically, the size that is relevant for breeding is obviously not going to the same as a head count. And, because effective populations are highly sensitive to bottlenecks you can get really small numbers even when the extant population at any given time may be large.
The PNAS paper makes some novel inferences, and I’ll set that to the side until I read the supplements. But I don’t think it’s crazy that population structure within Neanderthals could be leading to lower total genetic diversity.
Being unable to believe a small population could eventually fill your garden in France with stone tools may just be a failure to understand the timescale. It’s taken us just a few decades to fill the world with plastic junk. The Mousterian stone tool culture alone spans over 100,000 years.