Sequencing data suggests that there has been some form of gene flow between Neandertals and their sister lineage, Denisovans, which resulted in modern humans. It is estimated that one to three percent of a non-African human’s genome has been inherited from Neandertals, with coalescent models suggesting that 35 to 70 percent of the Neandertal genome is present in the DNA of modern humans.
In this study, the authors sought to reveal surviving lineages that potentially arose from a number of ancient predecessors by identifying the Neandertal sequences present in the DNA of modern humans. The authors hypothesised that introgressed sequences - whereby the genes from the gene pool of one species are introduced into that of another during the process of hybridisation - vary between individuals. Consequently, the authors predicted that by analysing the DNA sequence of contemporary humans, a significant portion of the Neandertal genome could be retrieved. A computation model was used to identify those Neandertal sequences that are present in the DNA of modern humans. Whole genome sequences of 379 European and 286 East Asian individuals were obtained to ascertain Neandertal lineages that are present in the DNA of modern humans. This approach made use of the previously developed statistic, S*. This statistic is calculated without using the Neandertal genome as a reference. Therefore, this statistic can be used without an ancient reference sequence, revealing huge potential for