Dr. Nicolas Zwyns is an archeologist at the University of UC Davis. He wrote his thesis on the dispersal of species 50000 years ago. He specializes in ancient human species in Asia — especially Denisovans. He specializes with the specific time range when modern humans come in and when older hominids began going extinct.
The name “Denisovan” implies that this group of hominids is just one population or species. In reality, Denisovans were more of what Dr. Zwyns referred to as a “metapopulation”. Early Denisovans existed nearly half a million years ago, and subsisted for quite some time after encountering modern humans. They are believed to have existed from the Middle East down to Southeast Asia. The Denisova Cave, the site from which Denisovans were originally discovered, is in the Altai Mountains in Siberia, Russia. During their time coexisting with modern humans, Denisovans are theorized to have interbred with Homo Sapiens. Some archeologists attribute modern tibetans’ ability to survive at high altitudes to Denisovan genetics.
The name “Denisovan” implies that this group of hominids is just one population or species. In reality, Denisovans were more of what Dr. Zwyns referred to as a “metapopulation”.
Early Denisovans existed nearly half a million years ago, and subsisted for quite some time after encountering modern humans. They are believed to have existed from the Middle East down to Southeast Asia. The Denisova Cave, the site from which Denisovans were originally discovered, is in the Altai Mountains in Siberia, Russia. During their time coexisting with modern humans, Denisovans are theorized to have interbred with Homo Sapiens. Some archeologists attribute modern tibetans’ ability to survive at high altitudes to Denisovan genetics.
The biological similarities and phylogenetic relationships between the Denisovans and humans are slightly complicated. The definition of two distinct species is that they are reproductively separate, caused by some sort of isolation — probably geographic in the case of modern humans. So how could many groups of humans (within the genus homo) breed? Nicolas Zwyns conveyed that the defining boundaries between human species were very obscure — even the definitions of reproductive isolation are not concrete. It takes a long interval of time for this separation to occur. So, despite Homo Sapiens and Denisovans being detached long enough for some diversity to occur, they were still biologically similar enough to mate. In this way, Denisovans were similar to neanderthals, who also interbred with humans.
Dr. Zwyns mentioned that the classification of biological organisms today into phylogenetic relationships is different than with ancient organisms. For old specimens, archeologists and paleontologists can only use bone structures and other phenotypic features from fossils which give less details than tissue samples. This causes some complexity in the classification of hominids. For instance, for just Homo Sapiens, or modern humans, there is great diversity in physical (phenotypic) features. People all around the world may look drastically different. However, among all these people, the real biological and phylogenetic (genotypic) difference is minimal. So, depending on physical characteristics may be unreliable.