Tracing the origin of our species through palaeogenomics

The recent breathtaking progress in whole genome sequencing technology allows access to the genomes both of ancient organisms and populations, including those now extinct. Despite the heavy degradation and the extremely low quantities of ancient DNA, it is sometimes possible to sequence an entire genome from a fossil. This enterprise has been successful in the case of fossilized remains from Neanderthals, a lineage of hominids that lived in Europe for 200,000 years and disappeared 30,000 years ago. An even greater surprise was the genome that has been obtained from a small finger bone preserved in a cave in the Siberian Altai Mountains. This genome revealed the existence of a human lineage previously unknown from the fossil record. The corresponding population mixed with the Neanderthals and the ancestors of the present day populations of South-East Asia. These hybridization events left different traces in the non-African human populations emphasizing the fact that we are genomic mosaics. The comparison of the different genomes also gives hints to how the genome of present-day populations was shaped and helps us to better understand which parts of our genetic make-up are responsible for the biological features of H. sapiens.