Monday, October 8, 2012

New Evidence to Human Evolution

New DNA evidence has been discovered in the genomes of modern hunter-gatherers of Africa. This evidence suggests that the development of the human species was driven by ethnic groups interbreeding rather than a superior original species

Members of the scientific community have long supported the “Y Chromosome Adam” theory. This theory explains that human genetic sequencing can be traced to one ancestor as the origin of the species. Genetically, Approximately 50,000 to 200,000 years ago, a doubling of the DAZ gene occurred in hominid males creating larger amounts of testosterone. The higher levels of testosterone led to the evolution of bigger and more developed brains

DNA evidence among modern hunter gathering tribes shows foreign-looking stretches of DNA not common amongst its original ancestors. The observations made of the Pygmies of Cameroon show that genetic differences in evolution like smell, taste, immunity, and a genetic variant that explains the short stature of the Pygmy people (4’11’’ avg. height). Similar foreign DNA could be found in other tribes separated by geography like the Hadza and Sandawe who have little to no intertribal contact.

Evidence suggests that “archaic” humans are the species involved like Neanderthals and other protohuman species more closely related to apes. They share ancient genetic material with “modern” species. The most notable fossil with similar genetic ties found of a protohuman is the skull of a “Homo Heidelbergensis”, a species existing 500,000 years ago and are ancestors to Neanderthals.

It is unclear whether this “ancient” DNA from primitive humans is helpful, harmful, or even relevant to humans today. The theory is still relatively incomplete but opens up the possibility that humans originated from different geographical positions. Also its important to note that Human evolution developed differently for species in different regions. Genetic similarities by no means guaranteed successful evolution as demonstrated by the point that ancient unsophisticated protohumans could exist alongside far more complex newly developing homo-sapiens.  

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