1Biology, The Pennsylvania State University, 2Anthropology, The Pennsylvania State University
April 14, 2016 3:30, Imperial Ballroom B
The Eurasian sympatry of Neandertals and anatomically modern humans has long sparked anthropological interest in the factors that potentially contributed to Neandertal extinction. Among many different hypotheses, one extinction model is that modern humans and Neandertals were disproportionately affected by exposure to novel infectious diseases that were transmitted during the period of spatiotemporal sympatry. A history of genetic admixture and thus direct contact between humans and Neandertals has recently been confirmed by comparisons of new archaic hominin paleogenome sequences with modern human genomes. Analyses of these data have also shown that Neandertal nuclear genome genetic diversity was likely considerably lower than that of the Eurasian anatomically modern humans with whom they came into contact, perhaps leaving their innate immune systems relatively more susceptible to novel pathogens. In this study, we compared levels of genetic diversity in genes for which genetic variation is hypothesized to benefit pathogen defense among Neandertals and African, European, and Asian modern humans, using available exome sequencing data (six chromosomes per population). Genetic diversity was estimated based on the number and allele frequencies of observed single nucleotide polymorphisms (SNPs) per population. We observed that Neandertal genetic diversity was relatively low in 73 innate immune system genes. In contrast, Neandertals and humans have similar levels and patterns of genetic diversity in nine major histocompatibility complex (MHC) genes. Thus, Neandertals may have been relatively more susceptible to some novel pathogens; differential pathogen-resistance should be considered as one potential contributing factor in their extinction, albeit cautiously.