While evangelicals will surely stick to their Adam and Eve story, DNA technology has greatly advanced our understanding of evolution and, in recent years, has uncovered the fact that most humans are hybrids. The last (to date) in a long line of hominids to walk the Earth, our species appeared in Africa about 130,000 years ago and began to disperse from that Continent about 80,000 years ago. However, earlier hominids had colonized Eurasia long before we left our homeland.
About 600,000 years ago, the lineage that would lead to humans split from one that would culminate in Neanderthals and their close cousins, the Denisovans. Based on DNA studies, these hominids diverged genetically and geographically about 350,000 years ago as Neanderthals spread into Europe and Western Asia while Denisovans occupied Eastern Asia, from Siberia to Indonesia. The latter group was unknown until a few fossils were discovered in a Siberian cave just two years ago; cool conditions within the cave served to protect DNA within the two bones and one tooth and subsequent studies demonstrated their close relationship to Neanderthals.
Of even more interest, DNA analysis of various human populations has demonstrated that early human migrants interbred with Neanderthals and Denisovans as they dispersed from Africa. While the latter two hominids became extinct about 30,000 years ago, we continue to carry some of their genes; 5% of the genome in humans of Eurasian descent is of Neanderthal origin and various populations of Southeast Asia, Melanesia and Australia have genomes that contain 4-5% Denisovan genes. The persistence of these genes in our DNA indicate that they conferred some benefit to early humans and were thus retained through the process of natural selection; only humans who are descendants of African populations do not possess this hybridism. Racist, white evangelicals may be interested to know that African Americans are pure Homo sapiens while they, themselves, are part Neanderthal.
