Genomic Glimpse into Human Migration

Footprints in sand

For African emigrants 125,000 to 60,000 years ago, the Arabian Peninsula was the first stop en route to populate Europe and Asia. However, genomic evidence has revealed that some put down roots in the desert instead of migrating north, and indigenous Arabs are their direct, present-day descendants.

“The indigenous Arab population was relatively isolated, and yet they flourished and developed, as did Europeans, as did Asians. It’s fascinating that all of these populations arose separately, yet became equally sophisticated and impressively advanced,” said Jason Mezey, an associate professor with a joint appointment in Biological Statistics and Computational Biology in CALS and in genetic medicine at Weill Cornell Medical College in New York City.

Mezey and the team of researchers had to look deeply at the genome to uncover these results, sequencing nearly entire genomes from more than 100 Qatari residents, over half of which had indigenous Bedouin ancestry. By comparing them with 1,092 genomes from populations around the world, the researchers constructed a global family tree. The indigenous Arabs branched off first from the initial African population, followed later by European and Asian limbs. Mezey and the study’s other authors note that the findings are more than a footnote to history: They show how evolutionary history informs modern-day medical genetics and the search for genes that cause disease. Diabetes, for example, affects about 22 percent of the Qatari population, and the scientists say that basing diabetes research and treatment development on Qataris’ precise genetic makeup—and their unique risk of disease—will better guide treatments.