Genetic studies have revealed that humans have moved more than previously thought, particularly over the last 10,000 years. The human genome was first sequenced in 2003. The human genome is 3 billion letters long, but people differ just one letter every thousand, on average. Based on genetics, we believe humans left Africa within the last 100,000 years and spread across the world replacing older species of humans. Ancestors of non-Africans lived side-by-side and interbred with Neanderthals about 40,000 years ago. Modern day human populations show a lot of mixing has happened within the last 2,000 years, with populations moving within and between continents. We are all the product of genetic relationships between ancient and modern human groups.
Original Article: https://theconversation.com/heres-how-genetics-helped-crack-the-history-of-human-migration-52918