Human Ancestry Traced to Two Divergent Populations, Revealing Complex Origins

A new study reveals that modern humans descended from at least two ancestral populations that diverged and reconnected long before human diversification across the planet. Researchers at the University of Cambridge, using data from the 1000 Genomes Project, discovered that modern humans originated from a mix of at least two ancestral populations that separated approximately 1.5 million years ago and reunited around 300,000 years ago. This challenges the traditional view of a single, linear evolutionary path. An innovative computational algorithm modeled how these ancient populations separated and merged to form Homo sapiens. One lineage contributed about 80% of the genetic heritage of modern humans, while the other contributed 20%. The study suggests a population bottleneck occurred in one group after separation, lasting nearly a million years. The minor genetic inheritance from the second population includes variants related to brain functions and neural processing. Unlike previous studies focusing on fossils or DNA from extinct relatives, this research relies solely on the analysis of DNA from contemporary humans, inferring the existence of ancestral populations not found in the fossil record. Possible ancestral lineages include Homo erectus and Homo heidelbergensis, but further research is needed.