A precious gift. An extinct species has passed its genes to modern humans: find out who it is (photo).

Many prefer to believe that humans emerged suddenly and neatly from a single common ancestor. However, as scientists learn more, it becomes increasingly evident that interbreeding with various hominins occurred and indeed contributed to shaping humanity into what we are today, reports Science Alert.

Much has been said about the Neanderthal and human branches of humanity, and according to scientists, it is becoming more apparent that in the past we frequently encountered another close relative — the Denisovans.

In a new review of existing research on Denisovan DNA, conducted by population geneticists Linda Ongaro and Emilia Huerta-Sanchez from Trinity College Dublin, the researchers demonstrated how the history of a people about whom we still know far too little has influenced human development.

According to the authors' findings, several populations of Denisovans, adapted to their environments across the Asian continent and beyond, repeatedly transmitted their genes to our ancient ancestors, providing humans with a set of advantages, much like what is known to have occurred with Neanderthals.

Regrettably, we still know very little about the Denisovans today. In comparison, the study of Neanderthal remains, graves, and artifacts has spanned several centuries, while academic familiarity with Denisovans has only recently begun and remains limited. Over the last few decades, only a few teeth and bones belonging to these extinct relatives have been discovered.

Genetic analyses of this species actually began only in 2010 — scientists examined a finger bone belonging to a woman. The results indicated that the remains belonged to a previously undocumented group of hominins that diverged from Neanderthals about 400,000 years ago. Researchers believe this likely occurred several hundred thousand years after Neanderthals began to differentiate from our own ancestors.

In recent years, our understanding of the range, culture, and adaptations of Denisovans has grown, hinting at a rich diversity of people with a genetic heritage stretching from Siberia to Southeast Asia and across Oceania even to the Americas. Yet we still know very little.

In previous studies, scientists utilized preserved segments of Denisovan DNA in modern human genomes and found evidence of at least three past events during which Denisovan genes entered the genetic structures of contemporary humans.

Among the genes inherited from Denisovans, sequences common in Tibetan populations have been identified, aiding our bodies in coping with relatively low oxygen levels. Additionally, DNA enhancing the immunity of Papuans and genes found among Inuit lineages that influence fat metabolism to better withstand cold have also been discovered.