Ancient DNA reveals origins of multiple sclerosis in Europe

Nature ^

[FarCenter]

More than 1,600 ancient genomes have helped to trace the roots of a host of genetic traits found in modern Europeans. The genomes suggest that many characteristics — including a heightened risk for multiple sclerosis — were carried to Europe by people who migrated to the continent in three distinct waves starting around 45,000 years ago.

The findings provide evidence that some of the regional variation in certain traits was caused by differences in migrants’ dispersal patterns. That contradicts the idea that genetic differences arose mainly as people adapted to conditions in specific locations in Europe.

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Europe was settled by anatomically modern humans in three main waves: hunter-gatherers reached Europe from Asia around 45,000 years ago; farmers arrived from the Middle East 11,000 years ago; pastoralists — animal herders — came from the steppes of western Asia and eastern Europe 5,000 years ago. ...

The researchers collected and sequenced DNA from 317 ancient skeletons found in Europe, most of which were between 3,000 and 11,000 years old1. They then combined these sequences with existing genomic data from more than 1,300 other ancient Eurasians.

By comparing the remains’ genetic markers, ages and burial locations, the scientists were able to draw a European family tree and migration map that revealed how genomic characteristics in a specific location changed as populations moved over time1. It showed, for instance, that the steppe pastoralists mainly went to the more northern parts of Europe, whereas the Middle Eastern farmers went to the south and west.

Some of these migrants completely replaced existing populations. Denmark, for instance, underwent two large population transitions, each within just a few generations2. Willerslev says that archaeological evidence and the speed of the transition suggest that the newcomers killed all the locals rather than driving them out or mixing with them.