Ancient human DNA hints at why a modern disease affects so many northern Europeans today

Ancient DNA helps explain why northern Europeans have a higher risk of multiple sclerosis than other ancestries: It’s a genetic legacy of horseback-riding cattle herders who swept into the region about 5,000 years ago. When a Bronze Age people called the Yamnaya moved from the steppes of what are now Ukraine and Russia into northwestern Europe, they carried gene variants that today are known to increase people’s risk of multiple sclerosis, researchers reported Wednesday.