Were the Neanderthals Human?

(a continuation of "Who was Mitochondrial Eve")

 

All Europeans have some small measure of Neanderthal DNA within the mix received from both parents.  Even so, no one alive today has been found to have a Neanderthal mitochondrial DNA signature or Y-chromosome DNA signature.  However, the mixed autosomal DNA within each of us proves that at some point in our ancestral past, people with European descent connect to Neanderthals. Many scientists classify Neanderthals as Homo sapiens neanderthalensis, a subset of the human branch, rather than a parallel branch. If we include the Neanderthals, our common maternal ancestor is further back in our ancestry than Mitochondrial Eve.  Neanderthals lived in Europe for about 350,000 years—and in the Middle East even longer.  Neanderthals’ ancestors lived in Africa 600,000 years ago—nearly three times older than the “Mitochondrial Eve” of the currently living human population.



This Neanderthal reconstruction is from the
Neanderthal Museum in Mettmann, Germany

My 23andMe DNA test and National Geographic DNA test both confirm that 3.2% of my uniquely human DNA markers are specifically Neanderthal.  That’s a small percent, but it says something special about my ancestry 25,000 years ago. Archeological evidence reveals Neanderthals to have lived in southern Europe up to about 25,000 years ago.  Their extinction was not exactly a genetic extinction, but rather, an assimilation.  My anatomically modern human ancestors moved from Africa through the Middle East and began to arrive in Europe about 43,000 years ago.  For nearly 20,000 years there existed an admixture of these populations—Neanderthals who resided in Europe, and the more sender, agile, anatomically modern humans, who arrived in Europe from the Levant.  Modern humans overtook the Neanderthals, yet they remained strong enough to leave their mark on 3.2% of my DNA.

Approximately a thousand human generations elapsed within the last 25,000 years.  That’s a lot of ancestors to document.  Of course many of our ancestral lineages converge together much more recently than 25,000 years ago.  My DNA suggests that 3.2% of those ancestors were Neanderthal, having distinctive mitochondrial DNA as found in my DNA comparison report. While Neanderthal autosomal DNA survives in the present human population, Neanderthal mitochondrial DNA at some point became extinct.  We don’t know when that extinction occurred, except to say that it is certainly more recent than our most recent archaeological samples of Neanderthal—more recent than 25,000 years ago.

If we bundle these Neanderthal ancestors into the category of what it means to be human, we push the convergence point of all humans back much further in time. The African ancestors of Neanderthals and anatomically modern humans converged between 600,000 and 800,000 years ago.  Personally, I classify Neanderthals as human.  They are certainly closer to anatomically modern humans than any other primate alive today, even with their own distinctive features included.

Anthropologists who study human evolution categorize these earlier ancestors as “archaic humans.”  If we look back 600,000 or more years, there are clear physiological differences between us and our ancestors in the archeological record.  There are also clear intellectual differences.  Should we consider these ancestors human?   It depends on our definition of human.  We have archaeological evidence that archaic humans utilized fire as early as a million years ago.  Our means of successfully controlling fire (at least some of the time) sets us apart from the rest of nature.  This mastery of fire included a complex level of imagination, discernment of risk, and very likely was combined with a sense of spirituality—all distinctive characteristics of humans. 

I’ll defend that the definition of human should be pushed back even further than our mastery of fire.  At some point in our ancestry there was a first person to imagine where the sun went after it set on the horizon at night.  This person, of course, had no idea where the sun escaped only to return on the opposite horizon the next morning. But somehow this early ancestor was able to imagine the question, and convey that message to others.  After the first human raises the question, of course there were others who pretended to know the answer.  This is a new level of socialization, again, as far as we know, distinct among humans.

The sun always returned on the other end of the sky the next morning.  These repeating cycles, built into nature itself, gave our ancestors the necessary level of order combined with mystery to begin a voyage of discovery.  That voyage led to the mastery of fire and to deeper questions.  Fire is here with us, but also in the sky. We need fire for warmth and light, yet fire can also destroy us.  Water destroys fire. We need water for life, yet water can also destroy us.  All the basic questions of life emerge out of our relationship with nature.

At what time in prehistory do we begin to ask questions of our experiences?

For countless generations, our ancestors went into the river to bathe, to cool down, to play, to drink.  For countless generations, our ancestors felt the flow of that water.  Yet at some point there was a first person who began to raise new questions.  Looking upstream, she pondered, “Where does this water begin?”  Looking downstream, she pondered, “Where does this water lead?”  These are human questions.  These questions are our own way to engage the mystery that surrounds us, the mystery that is in us. 

I think it’s these questions, ones that occurred very early in our ancestry, that make us human.