Friday, January 9, 2015

“You Neanderthal!”

Images this week from "Bing" photo collection

My early textbooks showed Neanderthal as dull-minded brutes – hunched over and wearing rough fur.  The question always came up… what happened to these guys?  What can we know about them?

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Neanderthals have been back in the news in recent years.  DNA has been collected from over 70 Neanderthal skeletons ( Europe and Asia) and a full Neanderthal genome have now been created. Neanderthal individuals coexisted with Homo sapiens in Europe something like 50-60,000 years ago.  They extended into Asia, but are best known in Central Europe.  (But not into Africa). This was a time of one of the great ice ages – so all life at this time had to deal with harsh cold conditions.

A recent artists view of how a Neanderthal individual might appear

Neanderthal, based on available data, had been identified as a similar but different species to man – called “Homo erectus”  … The word “Homo” (man) is the genus name and “erectus” (erect) in the species name 
The big surprise is that Homo sapiens and Neanderthal share about 99.5 % of the same genes.  But that last .5% makes all the difference!  (To show this is perspective the genome of chimpanzees share more than 98% of the same genes with modern humans)

For a quick explanation of the human genome project go here:
Model of  DNA molecule - all living cells use this coding molecule to carry the trait information of that organism  - it is replicated and passed on in each cell division.

Now the big surprise – when we examine the .5% difference between H sapiens and Neanderthal… Modern humans (H. sapiens) of European descent have between 1-4% of these genes found only in Neanderthal.  (Average about 2%)… The implications are huge – this means that H. sapiens exchanged genes with their human neighbors!  The classic Biological definition of a species is that individuals of the two groups must be able to mate and produce fertile offspring.  This indicates than that H sapiens and Neanderthal were in fact the same species. 

Another artist view of possible Neanderthal individual

Consider the wide differences found among human groups living in different habitats today. Eskimos over many generations have adapted to their cold climate by developing a smaller surface area to avoid heat loss, they are more compact and more rounded in body type.  (Natural selection...) Peoples of the equatorial zone developed dark skin to protect against the intense ultraviolet light. .  (The concept of race is a product of social –political divisions; largely formed during the age of cultural imperialism that went along with the period of Empire building.)  So it’s not difficult to stretch the concept of human to include Neanderthal.  They do not seem to fit the definition of a separate species.  This issue has been hotly debated in academic circles – and the newest DNA data seems to offer the most complete answer so far.  This calls into question the use of “Homo erectus” to label Neanderthal. 

One curiosity – a few years ago the body of a very early human was discovered frozen into the ice of the Austrian Alps – his tissue showed over a higher level of shared DNA with Neanderthals.  

So what can we know about Neanderthal people.  The best evidence comes from examination of their campsites and the articles that they made.
Neanderthal tools

·      The brain capacity was larger than modern H sapiens.  (Its unclear if that has implications)
·      Their fossil record extends from about 130,000 y.a. – 35000 y.a.
·      They lived in caves or huts made of stone or bones
·      Built fires
·      Wore animal fur for clothing
·      Developed moderately sophisticated stone tools
·      Developed systems of social cooperation (judging from camp site arrangements)
·      Buried their dead with care
·      Objects and camp site indicate that they probably had rituals requiring abstract thought

It is important to not lump all early “cave men” as the same – H. sapiens continued to develop and eventually formed the Cro magnon cave dwellers with their advanced cave painting and fine stone tools.
Homo sapiens - from the Cro Magnon times - identical  DNA trait information to humans today
Cro Magnon Cave Painting - France
Cro Magnon tools

Many questions are unanswered – We know nothing of the speech or Neanderthal folks.  Did they develop the ability to use words as abstract symbols?
Why did they disappear?
What was the relationship between Neanderthals and H. sapiens?
Are we guilty of denigrating them out of a sense of “specie-ism” (“we are the best”)?

So I wonder what traits I acquired in my 2% of Neanderthal genes...  We can never know – Next time you get on a crowded bus, look around at all the people and consider that a part of the Neanderthal trait information is still alive and well…