A recent groundbreaking genomic study led by researchers at McGill University and the University of California-Davis sheds new light on the question of human origin, suggesting that our history is not a single straight line but a complex web of interconnected branches stretching across the African continent.
Multiregional Hypothesis Gains Support
Contrary to the prevailing hypothesis, which proposes that Homo sapiens evolved from a distinct lineage around 150,000 years ago and spread through Europe and beyond, the new study supports the multiregional hypothesis. This alternative hypothesis suggests that before our species left Africa, there was continuous gene flow between at least two different populations, leading to a patchwork of co-existing populations that migrated and mixed.
Genetic data from 290 modern-day individuals in South Africa, Sierra Leone, Ethiopia, and Eurasia were analyzed, revealing evidence of high gene flow between their ancestors in eastern and western Africa. The researchers also incorporated genetic data from British individuals to account for gene flow back into Africa through colonial invasion, as well as an ancient Neanderthal genome from Croatia to consider Neanderthal genes mixing with humans outside Africa.
The study assumes the existence of two main lineages, representing distinct populations of early humans living in different parts of Africa around 400,000 years ago. These populations likely evolved independently for some time before merging due to shifts in wet and dry conditions across the continent between 140,000 and 100,000 years ago. This intertwined lineage, resulting from the merger, may have been the group that eventually left Africa for Europe approximately 50,000 years ago.
Multiple Waves of Migration
Interestingly, the genomic data suggests that the first humans in Africa departed for Europe around 10,000 years later than previously considered when compared to the genomes of individuals with European ancestry. Recent studies indicate the possibility of multiple waves of migration from Africa to Europe, further complicating the narrative of human migration.
With limited fossil records from that time period, scientists have turned to genomic sequencing as a powerful tool for tracing our ancestral footsteps. The more genetic data experts analyze, the more intricate and fascinating our story becomes.
In overall, this groundbreaking genomic study challenges the traditional view of a single origin for Homo sapiens and provides compelling evidence for a complex web of interconnected populations in Africa.
