Modern Homo sapiens is genetically a mix of species, including Neanderthals and Denisovans, a newly discovered hominin. This has big implications for human biology and medicine, but no one would have known if it wasn't for the brilliant Swedish scientist Svante Paabo. Paabo pioneered the new discipline of paleogenomics and won the Nobel Prize in medicine & physiology just this year!
More to explore:
Scientists sequence the entire mitochondrial genome of a Neanderthal