Genes from extinct human species allow the Tibetans to live in a low-oxygen environment, the Papuans got a good immune system and the Inuit (formerly called Eskimos) cope thanks to these genes with the arctic cold
The tree of life is not always a straight and tall tree; Sometimes it twists like a vine that momentarily embraces other tendrils before they continue to grow or wither. While much has been said about the Neanderthals, it turns out that the Denisovans - another extinct relative - played a decisive role in shaping modern humanity.
A recent study published in Nature Genetics by population geneticists Linda Ongro and Emilia Huerta-Sanchez of Trinity College Dublin sheds light on the genetic encounters between our ancestors and the Denisovans. The researchers describe at least three different events in which Denisovan populations transferred genes to modern humans, similar to what the Neanderthals did.
Denisovans: forgotten relatives
The Denisovans, who genetically diverged from the Neanderthals about 400,000 years ago, became a distinct group after they split from our ancestors. Their bones, discovered mainly in Denisova Cave in the Altai Mountains of Siberia, include a finger, teeth, jaw and skull fragments. Despite the limited findings, in-depth genetic analyzes have begun to reveal their genetic contribution.
In 2010, an analysis of a finger bone from a young girl showed that it contained both Denisovan and Neanderthal genes, because these two species interbred with our modern ancestors. Since then, studies have shown that the Denisovans were culturally and genetically diverse, living widely from Siberia to Oceania and even the Americas.
The influence of Denisovan genes
According to Ongro and Huerta-Sanchez, Denisovan genes left a significant mark on the modern genome. "Among these genes is a genetic locus that confers tolerance to hypoxia, i.e. to conditions of lack of oxygen, which makes a lot of sense since it was observed in Tibetan populations; Several genes that increase the immune system in native Papuans; And one that affects lipid metabolism and provides heat in response to cold, which gives an advantage to Inuit populations in the Arctic,” explained Dr. Ongro.
These genetic encounters add to the Neanderthal contributions, with which modern humans have dealt with plagues, shaped their body structure and even influenced their brain structure.
Genetics and evolutionary history
Ongro Huerta-Sanchez's review provides evidence that encounters between different groups of hominins were not rare events, but an integral part of human evolution. "The notion that we evolved in an orderly fashion from a single ancestor is wrong," Ungro emphasizes.
Further research revealed that at least three events of gene exchange occurred between different Denisovan populations and modern humans. These genes, preserved in modern genomes, allow scientists to build a broader picture of early human history.
Future studies and genetic inheritance
Despite the progress, many gaps remain in understanding the contribution of the Denisovans to the development of humans. Ongro notes that detailed genetic studies in understudied modern populations may reveal hidden genetic traces and provide further insights into the Denisovan heritage.
Combining genetic data with archaeological findings will help to complete the picture and tell a richer story about human development, with a deep understanding of mating processes between different species.
The findings indicate that the contribution of the Denisovans was not only expressed in individual encounters but was a central element in the biological development of modern man. The study emphasizes the need to continue to investigate the effects of encounters with extinct relatives on the human genome and the effect this has on our evolution.
More of the topic in Hayadan:
