27/11/2022

Original DFB – Neanderthal tendencies

Advance to The science bit – Back to Original Index
Back to Denton Family Bible

The Genographic Project’s first test was to see how much Neanderthal I had in my genes.

Current theories suggest that we derive from Homo heidelbergensis, a species first discovered in 1907 near Heidelberg, Germany – hence the name. This species emerged in Africa and between 400,000 to 300,000 years ago a group migrated north-west out of the continent, at some later stage split into two groups.

Neanderthal
Denisovans

Those who migrated west into Europe became known as Neanderthals and those who turned eastward evolved into Denisovans. They are termed Neanderthal merely because their first remains were discovered in the Neander valley, near Dusseldorf in Germany, and Denisovan because they were first discovered in the Denisova cave in Siberia (found in the 1970s but not properly understood until 2008). Both groups have been long extinct.

Comparative skulls

The stay-at-home Africans, Homo heidelbergensis, later evolved into a new species, Homo sapiens sapiens. Of slender build and bipedal, with an average brain size of 1350cc, homo sapiens sapiens had a rising forehead, very small eyebrow-ridges and a prominent chin – essentially much the same as we are today – and this species represents the only hominid existing today – us!

A number of haplotype mutations have been shown to have taken place within Africa before the next major northward migration. The ice in northern Europe had begun to melt and recede. As Africa became warmer and moister, areas of the Sahara became both passable and habitable. The animals habitually hunted by our ancestors roamed further north and we followed them. These hunters represented the first modern humans to leave Africa. All of us found outside Africa today derive from these groups that left the continent between 70,000 and 60,000 years ago.

This next wave of modern humans would of course have inevitably encountered those earlier migrants, the Neanderthals and Denisovans, during their travels. Neanderthals became extinct between 41,000 and 39,000 years ago. Around the same time as these earlier hominids were becoming extinctm some 40,000 years agom there was another climate change. Drought turned North Africa and the Middle East back into desert, effectively ‘slamming the door’ behind those modern northern migrants for 20,000 years. So my ancestors, maternal and paternal, had set off and could not return to Africa, thus prompting a continuing migration north, east or west.

However, there is evidence that there was ancestral interbreeding with the Neanderthals and Denisovans before their extinction. Most Europeans and Asians carry a memento of these (much maligned!) hominins; between 1% and 4% of their DNA is Neanderthal.

I’m not sure I should feel joy but I should mention my contentment that I prove to be down at the bottom end of that scale, my DNA being just 1.2% Neanderthal. I am also low compared with the Genographic Project’s current average of 2.1%. Perhaps it was just that my antecedents were late-arrivals or not very good at mixing with the neighbours?

My haplogroups have been tested and suggest I am R-Z8 (paternal) and K2A (maternal) – more below.

Of all those (when I last checked, some 740,000+) who have submitted material to the Genographic Project, I appear to be relatively unusual in that my paternal RZ-8 haplogroup is shared with only 2.8% (1 in 36) of the participants and my maternal K2A with just 0.3% (1 in 333).

Nice to feel special, but let’s look a little deeper.

Advance to The science bit – Back to Original Index
Back to Denton Family Bible

Leave a Reply

Your email address will not be published. Required fields are marked *