Phylogenetics is the study of evolutionary relationships between organisms. A good summary to human evolution is the wiki page: https://en.wikipedia.org/wiki/Hu

Phylogenetics is the study of evolutionary relationships between organisms. A good summary to human evolution is the wiki page: https://en.wikipedia.org/wiki/Human_evolutionary_genetics https://en.wikipedia.org/wiki/Human_evolutionary_genetics > I don't really understand how you can have multiple species that interbreed and then some go "extinct" but then we find "extinct" DNA in living ancestors. We have sequenced and reconstructed some of the Denisovan DNA https://en.wikipedia.org/wiki/Ancient_DNA#Human_aDNA https://en.wikipedia.org/wiki/Ancient_DNA#Human_aDNA This helps a lot, when combined with modern humans, and allows us to reconstruct our evolutionary relationship(s).