Neandertals are our closest evolutionary relatives. They first appeared around 400,000 years ago, ranged across Europe and western Asia, and became extinct approximately 30,000 years ago.
The draft Neandertal genome sequence being reported in Science represents about 60 percent of the entire genome. The genetic material that was sequenced came from single bones from three individual Neandertals.
The sequencing effort involved multiple steps to deal with the challenges of sequencing ancient DNA. The researchers removed as little material as possible from the bones, using a delicate dentist's drill so as not to damage the fossils, and they conducted their lab research using sterile "clean-room" conditions, to avoid contaminating the material with DNA from present-day humans and other organisms. They also weeded out the much more abundant microbial DNA that had colonized the bones since the individuals died.
Modern humans and Neandertals are so closely related that a comparison of their genomes must take into account the fact that for any particular part of the genome, a single modern human and a single Neandertal could be more similar to each other than two modern humans would be.
Most of what we know about genetic variation among humans today is based on European populations. Seeking a broader picture, Pbo and his colleagues sequenced the genomes of five present-day humans from southern Africa, West Africa, Papua New Guinea, China and France, and compared the Neandertal genome to the genomes of these individuals.
The Neandertal genome sequence proved to be slightly more similar to those of the non-African individuals.
More specifically, at any randomly chosen point in the genome where the sequence of two of the modern-day humans differed, there was a slightly
|Contact: Natasha Pinol|
American Association for the Advancement of Science