Tuesday, 21 August 2012

Neanderthals vs. Cro-Magnon



Neanderthals vs. Cro-Magnon
Kate Lowth BIOL 1020 Blog Post


In 1856 a few miners discovered the skull of the now known Neanderthal in a Neander Valley cave in Germany. As this was around the time of Darwin, speculation about an earlier human species arose. Scientists have since been debating whether or not the Neanderthal's have a place in human evolution.
A Neanderthal skull on the left, Cro-Magnon on the right. 
Neanderthals and Cro-Magnon man coexisted some 100,00 years ago but for whatever reason 30,000 years ago, the Neanderthals began to disappear. Just as the disappearance of the Neanderthals was noted, the first trace of a modern human also became evident.

It has always been suspected that in the years of the Neanderthals and Cro-Magnon man, the two species interbred. Experts presume the mating between species occurred as they likely crossed paths during thousands of years of European c
ohabitation.

It has now been proven that if any interbreeding between these two species occurred, it was far too insignificant for the Neanderthals DNA to be carried though evolution. As stated in the article, the thought of interbreeding was re-spiked when in 1998 a young boys skeleton was discovered in Portugal. His skeleton resembled both a Cro-Magnon and Neanderthals skeleton. The twist in this finding was that the boy lived after the Neanderthals, suggesting that features, hence DNA had been possibly passed on. However, genetic evidence has proved otherwise, all due to one little cell, the mitochondria.

Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. It was this little amount of DNA that allowed scientists to analyse if there were a difference in the two species. 

Reconstructed Neanderthal and Cro-Magnon.
A comparison of DNA from a Neanderthal specimen and an alive human was done to examine any differences between the two. It proved that the differences in the mitochondrial DNA suggested the two species were definitely different. This comparison of DNA sequences saw that modern living humans and Cro-Magnon still share the same DNA sequences, as they were “indistinguishable” from one another. The link between modern humans and Neanderthals however, resulted in a distinguishing difference.

At the end of the day, none of us were there so we will never know the exact truth of the matter. Some say that it would have been impossible for the two species to not mate as Pettitt statesevery colonisation in history has ended with the conquerors and conquered interbreeding”. And others say that if there was interbreeding it was too insignificant. Either way DNA has proved that there is an insignificant to no evidence that the Neanderthals genes survived evolution. 

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