Discovery of an unknown fragment of human evolution through a new genetic tool

2025/03/19 Galarraga Aiestaran, Ana - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa
• Genetika

According to the most accepted approach, Homo sapiens first appeared in Africa 200,000-300-000 years ago from a single lineage. Now, however, researchers at the University of Cambridge have come to another conclusion, using an innovative genetic analysis: sapiens are descendants of two species that hybridized 300,000 years ago.

It is known that sapiens and Neanderthals hybridized about 50,000 years ago. Genetic studies have shown that 2-4% of our genome is of Neanderthal origin. In contrast, current research has shown that these two species showed greater hybridization, with one leaving an 80% trace and the other leaving the rest.

To reach this conclusion, they have used an algorithm called cobraa and analyzed the DNAs of the Genome 1000 Project (1000GP) and the Human Genome Diversity Project (HGDP). These projects collect data from current genomes of different origins, from which the genetic history of the species has been rewritten by the cobraa algorithm.

Through this, they have discovered that these two Sapiens ancestors had a common ancestor 1.5 million years ago and, after their separation, had different destinies. The human that left the greatest mark on our genome suffered a serious bottleneck; it spread from the small population that remained and also contributed to the genomes of Denisovans and Neanderthals. The other species, which contributed 20%, mainly left in us genes related to brain function and neuronal processing.

The researchers admit that they could not ascertain what these two species were, but mention Homo erectus and Homo heildelbergensis. The study has been published in the open journal Nature Genetics.