And that's why birds do it, bees do it
Even educated fleas do it
Let's do it, let's fall in love
In Spain, the best upper sets do it
Lithuanians and Latts do it
Let's do it, let's fall in love
— Cole Porter, Let's Do It (1928)
Some interesting results about the last species in the genus Homo have been coming in lately. The evolutionary events of the last ~500,000 years which culminated in the dominance of Homo sapiens are starting to come into focus. This report is from Science Daily (December 18, 2013).
The most complete sequence to date of the Neanderthal genome, using DNA extracted from a woman's toe bone that dates back 50,000 years, reveals a long history of interbreeding among at least four different types of early humans living in Europe and Asia at that time, according to University of California, Berkeley, scientists...
The comparison shows that Neanderthals and Denisovans are very closely related, and that their common ancestor split off from the ancestors of modern humans about 400,000 years ago. Neanderthals and Denisovans split about 300,000 years ago.
[image above, Family tree of the four groups of early humans living in Eurasia 50,000 years ago and the lingering genetic heritage (red arrows) due to interbreeding, with some edits I made with regard to the "common ancestor" and the "unknown hominin", click to enlarge]
Though Denisovans and Neanderthals eventually died out, they left behind bits of their genetic heritage because they occasionally interbred with modern humans. The research team estimates that between 1.5 and 2.1 percent of the genomes of modern non-Africans can be traced to Neanthertals.
Denisovans also left genetic traces in modern humans, though only in some Oceanic and Asian populations. The genomes of Australian aborigines, New Guineans and some Pacific Islanders are about 6 percent Denisovan genes, according to earlier studies. The new analysis finds that the genomes of Han Chinese and other mainland Asian populations, as well as of native Americans, contain about 0.2 percent Denisovan genes.
The genome comparisons also show that Denisovans interbred with a mysterious fourth group of early humans also living in Eurasia at the time. That group had split from the others more than a million years ago, and may have been the group of human ancestors known as Homo erectus, which fossils show was living in Europe and Asia a million or more years ago.
Even a casual glance at the first image above shows that, regardless of species, everybody was ... keeping busy!
John Hawks is...
... so tired of diagrams with arbitrary arrows that show "migrations" in the past. Time for arrows that show breeding relationships we can really document. I obviously cannot include many living populations in a graphic like this, but hopefully it communicates the complexity that we've discovered!
Pleistocene Hook-Ups, click to enlarge
Alan Cooper, who participated in the study, said it best—
Alan Cooper, a professor at the Australian Centre for Ancient DNA at the University of Adelaide, says the study "completely rewrites what we know about human evolutionary history".
"We now have a reasonably definitive picture of the mixing and matching of [hominin] groups through time," he says.
And according to Cooper, the research reveals that "everyone is bonking everyone else … it's quite impressive".
Yes, it is quite impressive!
It's good to see that some things don't change. Hell, I wish I were doing it right now...
Based on my own extensive research at great cost (I interviewed myself about my patchy success in the bonkosphere over the past 40 years) I can classify modern humans into two groups:
1. The Unlucky - those who wish they were doing it.
2. The Lucky - those who wish they were doing it with someone else.
I thank you. Please throw something in my hat.
Posted by: Oliver | 12/23/2013 at 02:40 PM