An ancient period of savage warfare destroyed the majority of men on Earth but left the female population largely unscathed, scientists have claimed. A team from Stanford University said The Old World (Europe, Asia, Africa and the Middle East) became a bloodbath between 5,000 and 7,000 years ago.
The slaughter was so intense that it reduced the male population to one-twentieth of its original level. Two bright Stanford undergraduates studying maths and sociology worked with a professor of computing to offer a new solution to explain the ‘Neolithic Y-chromosome bottleneck’ when human genetic diversity suddenly plummeted across the planet.
Fathers pass on the Y chromosome to their son, so a sudden drop in diversity suggests large numbers of men were dying before having sex and producing children.
In a paper published in Nature, the team dismissed previous hypotheses which blamed disease or the ‘founder effect’, which describes the reduction in genetic variation when a small number of individuals establish a population which goes on to grow to a large clan or civilisation.
Instead, they blamed ‘competition’ between ‘patrilineal kin groups’, which are clans, tribes or some other social grouping formed from people who share a common ancestor. ‘The presence of such groups results in violent intergroup competition preferentially taking place between members of male descent groups, instead of between unrelated individuals,’ the team wrote.
‘Casualties from intergroup competition then tend to cluster among related males, and group extinction is effectively the extinction of lineages.’ ‘If the primary unit of sociopolitical competition is the patrilineal corporate kin group, deaths from intergroup competition, whether in feuds or open warfare, are not randomly distributed, but tend to cluster on the genealogical tree of males,’ they added.
What this theory suggests is that at some point just before the earliest known civilisation was formed by the Sumerians in about 4000 BC, humanity began forming into large family clans.
It is likely that powerful clans killed off the men from opposing tribes and then captured the women. Over time, this led to the extinction of a large number of men and the traumatic survival of their female relatives, who would suddenly have found themselves at the mercy of another tribe.
Estimates of the human population on Earth vary between about five and 20 million at the time range between five and 20 million. This could mean that up to 9.5 million men were killed or prevented from reproducing.
Source: Metro Uk
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