A team of scientists led by Dr. Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has announced the completion of the sequencing of the DNA of a Neanderthal (skeleton photos ©Claire Houck) taken from a toe bone discovered in 2010 in a Siberian cave.
In 2010, the same team presented the first draft of a Neanderthal DNA obtained from three bones found in a cave in Croatia. In the next two years, those scientists have developed techniques that allowed them to repeatedly sequence the DNA taken from the new sample.
Dr. Svante Pääbo is one of the founders of paleogenetics, the discipline that studies the DNA of ancient humans. In 2006 he announced the project to reconstruct the DNA of Neanderthals, a problem not easily solved. It’s estimated that Neanderthals became extinct more than 30,000 years ago and this has made it difficult to find samples that contain DNA in a state good enough that it can be fully sequenced. Another problem was constituted by contamination of the samples by bacteria but also by anyone who had handled the bones the samples were taken from.
Early research made it possible to extract some Neanderthals DNA sequences in 1997 and in 2000 the sequencing of the mitochondrial DNA of a Neanderthal was announced. Genetic techniques have made big leaps forward over the last 15 years and, together with patience in the search for DNA samples of adequate quality for a complete sequencing, finally in the last two years Dr. Svante Pääbo’s project has achieved the desired results.
The data on genome sequenced are freely available in a section of the Max Planck Institute for Evolutionary Anthropology website in BAM format, the binary version of the format used to write alignments of nucleotide sequences in large quantities. In bioinformatics, the alignment of sequences allows to compare two or more nucleic acid sequences, in this case DNA sequences, to detect similarities between them.
This new research will allow deeper investigation of the comparison between Neanderthals and modern humans DNA. The problem of the exact relation between these two species and the possibility that they are two subspecies of the same species have been dividing scientists for quite some time. Obviously, more complete samples of Neanderthal DNA will be of great help in this type of investigation, also to understand if there was some form of interbreeding between Neanderthals and modern humans.
Another comparison that they can make is with the Denisovans, a possible additional species of hominid that lived with both Neanderthal and modern humans. Various sequencing of mitochondrial and nuclear DNA of a Denisovan have been made in recent years, also by Dr. Svante Pääbo’s team.
Those comparisons may provide new information on the evolution of these species of hominids and maybe will give us some clue about Neanderthals’ extinction. Several theories have been proposed to explain it, even recently, but the issue is still open. These investigations need time to complete but definitely will allow us to better understand the Neanderthals, whose story eventually crossed with that of modern humans.