Wednesday, 22 January 2014

DNA, Weapons, War and Human Evolution

It is an exciting time for DNA research. We learn more about our ancient history all the time.

We are able to follow the movements of people throughout the world by their DNA. Humans left Africa and migrated throughout the world, picking up genes from other human subspecies such as the Neanderthals, Desinovan, and others not yet identified. The map below from Wikapedia shows the location of males by concentrations of their "Y" haplogroup which makes men male and which is passed from father to son with relative little change. The concentrations shown are before Europeans colonized and took over North and South America and Australia. There are likely some mistakes in the map but it is close enough for discussion.

This map can be viewed as a map of conquest. The ancestors of male "Y" Hapblogroups shown above either took over territory by killing other males or they were the first and only people in their area and were successful in keeping other males out.

Take a look at the "R" haplogroup. It is believed to have originated in West Asia.  But it has spread in a number areas, including into Africa, North America, and in Asia. And in most cases killing and replacing the males who were there before.

It is also likely that patterns of conquest were different before and after agriculture became important. Prior to agriculture all humans were hunter gathers. Defeated male groups were of no value to the victor and would have been exterminated. (Not so the attractive females).

After agriculture defeated males did have value. They became serfs and peasants who provided some of their production to their conquerors. So after agriculture wholesale destruction of males in the conquered tribe became much less common - hence our modern situation of numerous male "Y" haplogroups living together.

The map below shows the distribution of the male haplogroup "Q", which is inherited from father to son. Most male Native Americans share this haplogroup and it is clear from the map that it spread from north east Asia into America. It was probably with the first migrants who settled both American continents.

The map below shows the distribution of the male haplogroup "C3".  People with this haplogroup clearly came from Asia and judging from the map, was a later migration into the new world and did not go further south, blocked by earlier migrants to the new world. But presumably these males conquered and displaced "Q" males who had previously colonized and populated the areas of northeast Asia and northwest North America.

The map below shows the distribution of the male Y Chromosome "R1-M173" Y-DNA, passed from father to son. It is a fairly recent haplogroup but has expanded its range very wide, and at the expense of the men who previously occupied the lands now occupied by R M173. (Many scientists believe that the R M173) in North America is post Columbian. But it appears to me that there is too high a concentration of R M-173 in northeast North America and too few in the rest of the America's.  It is likely the result of a much older occupation. 

Modern humans would have replaced Neanderthals, Desinovians and other archaic humans through war. All the males would have been killed - a hunter gatherer has no need for more men.  But the attractive women would have been kept and contributed to the gene pool of the victors.

Technology would have been a tremendous advantage. The first men who successfully fielded spear throwers, slings, and bow and arrow would have had a huge advantage over neighboring tribes who would quickly have been conquered.

We have numerous examples of this in the modern world. Europeans had steel weapons and firearms. They quickly conquered much of the rest of the world. But males had value in these conquered lands and were not exterminated.

Genghis Khan and his sons created an enormous empire. Their advantage was superior bow and arrows which they could fire from horseback.  They conquered much of Eurasia and happily donated their DNA.

Evolution of humans would have been greatly accelerated by large scale conquests.  We don't know when or where the bow and arrow was invented, but the inventors were probably smarter than the people who did not invent these weapons. The males of the tribes who had the bow would have happily conquered the tribes who did not have this advantage and they would have contributed their DNA to many conquered tribes.