<\/span><\/p>\n Genes that significantly increase risk of developing multiple sclerosis were introduced to northwestern Europe by herders who migrated from the east around 5,000 years ago. <\/span>SayoStudio<\/span><\/p>\n More than 1.8 million people<\/a> around the world have the autoimmune disease multiple sclerosis (MS). The condition, in which a person\u2019s immune system attacks their brain and spinal cord, is most common in northern Europe, but researchers haven\u2019t been entirely sure why.<\/p>\n A new study of ancient DNA, published Wednesday in the journal Nature<\/em><\/a>, sheds light on this trend, suggesting herders who migrated to Europe from western Eurasia around 5,000 years ago carried genetic variants linked to MS. These variants grew in prevalence at the time and contribute to an increased risk for the disease today, the paper authors write.<\/p>\n \u201cThis is a tour de force,\u201d Llu\u00eds Quintana-Murci<\/a>, a population geneticist at the Pasteur Institute in Paris who did not contribute to the findings, tells Nature News<\/em><\/a>\u2019 Sara Reardon.<\/p>\n The study accompanies three<\/a> other<\/a> new papers<\/a> in Nature<\/em> investigating ancient DNA in Europe and Asia. One of those found that genes linked to an increased risk for diabetes and Alzheimer\u2019s disease were carried by hunter-gatherers.<\/p>\n \u201cProcesses that were occurring many thousands of years ago are having these really pronounced and profound effects on the health and longevity of people in the present,\u201d Evan Irving-Pease<\/a>, an author of all four of the studies and a population geneticist at the University of Copenhagen in Denmark, tells the Washington Post<\/em><\/a>\u2019s Carolyn Y. Johnson.<\/p>\n Researchers explored this history by sequencing ancient genomes and comparing them to modern DNA. The team examined ancient DNA from bones and teeth dating to the Mesolithic period and Bronze Age, as well as new genomes collected from Medieval times. They studied this data against DNA from 410,000 white British people included in the modern U.K. Biobank<\/a>.<\/p>\n Major migrations had a strong impact on genetic diversity in western Eurasia, the authors write. Hunter-gatherers entered the picture around 45,000 years ago, farmers came from the Middle East around 11,000 years ago and herders migrated from the Pontic Steppe<\/a>, a grassland region in the Balkans and western Asia, around 5,000 years ago.<\/p>\n These herders, known as the Yamnaya, rode horses and drove ox-drawn carts, writes Science News<\/em><\/a>\u2019 Bruce Bower. And they buried their dead with gold and jewelry, per the New York Times<\/em><\/a>\u2019 Carl Zimmer. Most people in northern Europe today can trace their ancestry to this group.<\/p>\n Major migrations had a strong impact on genetic diversity in western Eurasia, the authors write. Hunter-gatherers entered the picture around 45,000 years ago, farmers came from the Middle East around 11,000 years ago and herders migrated from the Pontic Steppe<\/a>, a grassland region in the Balkans and western Asia, around 5,000 years ago.<\/p>\n These herders, known as the Yamnaya, rode horses and drove ox-drawn carts, writes Science News<\/em><\/a>\u2019 Bruce Bower. And they buried their dead with gold and jewelry, per the New York Times<\/em><\/a>\u2019 Carl Zimmer. Most people in northern Europe today can trace their ancestry to this group.<\/p>\n The researchers found that variants linked to MS arose around 5,000 years ago in the Yamnaya, who spread their genes when they got to northern Europe. These variants increased in prevalence for the steppe population, and later, in the European population, which signaled to the scientists that that they might have provided an evolutionary advantage.<\/p>\n \u201cThese variants that are causing the high risk of multiple sclerosis today must in the past have had a benefit,\u201d Eske Willerslev<\/a>, a geneticist at the University of Copenhagen and a leader of the research, tells the New York Times<\/em>.<\/p>\n Continue reading this interesting story from The Smithsonian<\/a><\/p>\n ———-<\/p>\n
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