Thursday, May 30, 2019

When Herders And Foragers First Met In Africa, They Did What Comes Naturally To Humans

New ancient DNA from Africa sheds light on how the first herders in Africa found mates among Africa's foragers. 
DNA analysis shows that African herders and foragers mated with each other in two phases, says a team led by archaeologist Mary Prendergast of Saint Louis University in Madrid. After entering northeastern Africa from the Middle East around 8,000 years ago, herders swapped DNA with native foragers between roughly 6,000 and 5,000 years ago. Herders possessing some forager heritage then trekked about halfway down the continent and mated with eastern African foragers around 4,000 years ago, the scientists report online May 30 in Science. . . .
Early African herders inherited about 20 percent of their DNA from foragers, mostly via mating that occurred before 5,000 years ago, the scientists say. Herders then spread rapidly throughout eastern Africa after 3,300 years ago, mating little with foragers along the way. 
From here. The source paper is:

M.E. Prendergast et al. Ancient DNA reveals a multistep spread of the first herders into sub-Saharan Africa. Science. Published online May 30, 2019. doi:10.1126/science.aaw6275.

The abstract is as follows:
How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multi-phase model in which admixture between northeastern African-related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African-related groups occurred by the Iron Age. These findings support several movements of food producers, while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.

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