Genes-R-Us — Setting the Neanderthal record straight
Posted: Wednesday, January 11, 2012 5:00 pm
My paleoanthropologist obsession first occurred back in elementary school. I can now refine those early career musings to “genomic-paleoanthropologist.” But who knew back then? The concept of sequencing a Neanderthal genome was well beyond even science fiction. And I certainly was ignorant of my Neanderthal ancestry back then.
In May 2010 scientists had access to the first Neanderthal genome which was sequenced from the skeletal remains of three females living in Croatia about 40,000 years ago. That same year the Denisova genome, sequenced from human remains found in Siberia and equally as old, was reported as distinct from both from Neanderthal and “modern” human genomes.
By comparing the genomes of the Neanderthals and the Denisovans to those of multiple people groups alive today, scientists have found that the first anatomically “modern” humans, the Cro-Magnons who are our direct ancestors not only coexisted but produced viable offspring with these two “archaic” populations.
This was BIG news even in the popular press as Cro-Magnons were not supposed to have interbred with Neanderthals (or Denisovans).
Advancements in DNA purification and amplification, in addition to improvement in sequencing hardware and software, enabled publication of these two “archaic” genomes.
Towards the end of 2011, the direct-to-consumer (DTC) genetic testing company that I use began providing their customers with the percentage of Neanderthal in their DNA.
The range of Neanderthal DNA for persons with any European or Asian ancestry is 1-4 percent. No trace of Neanderthal DNA is found in 100 percent African populations. Most African-Americans, however, are not 100 percent African, so they will carry some Neanderthal DNA. Today’s Melanesian populations are the primary carriers of around 5 percent of Denisovan DNA.
The Neanderthals now appear to have left the Middle East, not Africa, to spread into Europe and Asia.
This definitely puts a crinkle in the simple “out of Africa” story for humans.
An amount of 1-4 percent has more significance than it may sound. The variability in DNA for current world populations is large enough to include our Neanderthal ancestors.
I carry an estimated 3.0 percent Neanderthal DNA in my genome compared to my husband’s estimated 2.4 percent. For those self-reporting Northern European ancestry, that puts me in the 90th percentile compared to my husband’s 26th percentile
Why do I have more? Perhaps my Neanderthal ancestors were just better looking to the Cro-Magnons or at least more willing, shall we say, to step out of their skins …
Given that I have more than the average amount of Neanderthal DNA, allow me to set the record straight about my much misunderstood ancestors. Neanderthals were as fully human as you and I are. They had family units, cared for their sick, buried their dead, controlled fire, made tools and enjoyed flute music.
Neanderthals displayed all colors of eyes and hair and light skin that we see in Caucasians today. Their brains were the largest in human history. They had the same FOX2 gene as we do that is responsible for language and they were anatomically equipped for language.
They were better adapted to the cold of the times due to their larger nasal capacity and their shorter, stockier builds that required 30 percent more calories than the “modern” human. They were really strong due to their dense and highly muscled physique. They had a pelvic bone structure that would slow them down compared to Cro-Magnons.
Those famous Neanderthal protruding brow ridges were not present at birth as they developed later in adulthood. A Neanderthal person would pass for a Caucasian today, given an update in hair style and attire.
In 1994, 12 Neanderthal skeletons were discovered in Spain spanning age ranges from adulthood to infant. Based on the artifacts, archeologists believe that all 12 were a social unit. A total of three mtDNA lineages, indicating maternal ancestry, were represented in the 12 individuals. All three adult males shared the same mtDNA lineages; whereas the three adult females did not.
This indicates a childbearing/family arrangement where women leave their families to join their men and the primary social groups were based on male kinship. This is still quite common in many societies today.
Scientists have been able to relate the differences between the Neanderthal and our DNA down to specific genes in many cases. Those genes, when function was known, have been associated with type II diabetes, Down’s syndrome, autism, schizophrenia, bone growth, reproduction and the immune system.
Wow it has never been easier (or cheaper) to find out just how “archaic” you really are.
Editor’s note: Nancy Miller Latimer has worked in scientific research and development for 27 years. She blogs at neuronalbeauty.blogspot.com.
published in The Messenger 1.11.12