Scientists have uncovered evidence of ancient ancestors in human DNA, shedding light on our genetic composition. Researchers have detected genetic material from two unknown groups of hominins, a category of primates that includes homo sapiens and neanderthals. One group originated in Africa approximately 50,000 years ago, while the other “super archaic” lineage dates back 1.8 million years.
These ancestral groups are believed to have interbred with Denisovans, another type of hominins that have since disappeared, such as neanderthals. The genetic mixing occurred in Eurasia, with Denisovans passing on the “super-archaic” DNA to homo sapiens generations later. It is estimated that modern humans carry a similar amount of “ghost DNA” as neanderthals, accounting for approximately 1 percent of their genome.
Yulin Zhang, a researcher from UC Berkeley involved in the study, noted that around 2 percent of the modern human genome comes from archaic hominins. Both modern-day Africans and non-African populations have inherited comparable amounts of ghost ancestry, with each individual possessing about 0.5 to 1 percent of their genome from this ancient lineage.
Arjun Biddanda, a postdoctoral researcher at Johns Hopkins University and a study co-author, expressed excitement over the discovery of genetic contributions from a human lineage that existed over a million years ago. The presence of “ghost DNA” was previously assumed to be unique to modern-day African populations, but the research reveals its existence in both African and non-African populations, suggesting widespread interbreeding before homo sapiens migrated beyond Africa.
These findings support the notion that modern homo sapiens are a mosaic of extinct hominins’ genes, indicating prolonged interbreeding among different groups over millennia to give rise to the diverse human population seen today.
