Neanderthals, Homo neanderthalensis, were a species of prehistoric hominid that existed 30,000 to 400,000 years ago. They were the closest relative to humans, but it is thought that humans drove them to extinction.
Now led by ancient-DNA expert Svante Pääbo of Germany's Max Planck Institute for Evolutionary Anthropology, the Neanderthal genome has been sequenced. Roughly a decade after the first full sequencing of a human genome, the Neanderthal genome stands complete, with the full study appearing in the journal Science.
The DNA for the project came from bone fragments of three female Neanderthals excavated in the late 1970s and early 1980s from a cave in Croatia. The ancient hominids lived approximately 38,000 to 40,000 years ago.
It is speculated that Homo sapiens (humans), which first evolved in the plains of Africa, may have interbred with Neanderthals as they spread out across the Middle East and North Africa. The new DNA evidence indicates that this indeed occurred, but that it occurred far earlier than previously thought -- approximately 80,000 years ago.
Humans and Neanderthals diverged between 270,000 to 440,000 years ago, but thanks to interbreeding, some Neanderthal genetic traits survive to this day. Additionally, Neanderthals and humans both appear to have evolved similar traits that accomplished the same goals, but were not genetically identical (the result of interbreeding).
The project is a very difficult one. Over 97 percent of the sample DNA is bacterial and fungal DNA and must be painstakingly removed. Meanwhile researchers must avoid contaminating the samples with their own DNA. Researchers have been building a genome billions of base pairs long, using fragments 40 to 50 base pairs in length. Describes Pääbo, "We used half a gram of bones to produce the 3 billion base pairs. I really thought until six or seven years ago that it would remain impossible, at least for my lifetime, to sequence the entire genome."
Researchers found that sequenced human genomes from one San from southern Africa, one Yoruba from West Africa, one Papua New Guinean, one Han Chinese and one French person shared 1 to 4 percent common genomic material with Neanderthals, the result of these people's ancient ancestors interbreeding with the close relative. The genes appear to offer no benefit and be randomly placed. Additionally the transfer appears one way, from Neanderthals to humans.
The new work is not without controversy. The hard evidence it provides is discomforting for those whose religious doctrines claim that the Earth is less than 10,000 years old. Furthermore, it provides further evidence of how humans and other hominids evolved, a concept that is opposed by several religions.
Still, those more inclined to believe in science will certainly appreciate this magnificent study. Computational biologist Webb Miller, part of a Penn State team, a member of the team that sequenced the Woolly Mammoth and "Otzi" iceman genome cheers, "This is a way cool paper. I think it's really fascinating. Some [scientists] will love it and some of them will hate it. It's great science."