Tomislav Maričić

Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans. Anatomically modern humans were in Africa from some point after 200,000 years ago and reached Eurasia rather later. Meanwhile, archaic hominins — including the Neanderthals — had been in Eurasia from at least 230,000 years ago and disappear from the fossil record only about 30,000 years ago. The genome of a female archaic hominin from Denisova Cave in southern Siberia has now been sequenced from DNA extracted from a finger bone. The group to which this 'Denisovan' individual belonged shares a common origin with Neanderthals and, although it was not involved in the putative gene flow from Neanderthals into Eurasians, it contributed 4–6% of the genomes of present-day Melanesians. In addition, the morphology of a tooth with a mitochondrial genome very similar to that of the finger bone suggests that these hominins are evolutionarily distinct from both Neanderthals and modern humans. Using DNA from a finger bone, the genome of an archaic hominin from southern Siberia has been sequenced to about 1.9-fold coverage. The group to which this individual belonged shares a common origin with Neanderthals, and although it was not involved in the putative gene flow from Neanderthals into Eurasians, it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. A tooth whose mitochondrial genome is very similar to that of the finger bone further suggests that these hominins are evolutionarily distinct from Neanderthals and modern humans.

To date, the only Neandertal genome that has been sequenced to high quality is from an individual found in Southern Siberia. We sequenced the genome of a female Neandertal from ~50,000 years ago from Vindija Cave, Croatia, to ~30-fold genomic coverage. She carried 1.6 differences per 10,000 base pairs between the two copies of her genome, fewer than present-day humans, suggesting that Neandertal populations were of small size. Our analyses indicate that she was more closely related to the Neandertals that mixed with the ancestors of present-day humans living outside of sub-Saharan Africa than the previously sequenced Neandertal from Siberia, allowing 10 to 20% more Neandertal DNA to be identified in present-day humans, including variants involved in low-density lipoprotein cholesterol concentrations, schizophrenia, and other diseases.

BACKGROUND: To utilize the power of high-throughput sequencers, target enrichment methods have been developed. The majority of these require reagents and equipment that are only available from commercial vendors and are not suitable for the targets that are a few kilobases in length. METHODOLOGY/PRINCIPAL FINDINGS: We describe a novel and economical method in which custom made long-range PCR products are used to capture complete human mitochondrial genomes from complex DNA mixtures. We use the method to capture 46 complete mitochondrial genomes in parallel and we sequence them on a single lane of an Illumina GA(II) instrument. CONCLUSIONS/SIGNIFICANCE: This method is economical and simple and particularly suitable for targets that can be amplified by PCR and do not contain highly repetitive sequences such as mtDNA. It has applications in population genetics and forensics, as well as studies of ancient DNA.