1Department of Ecology and Evolutionary Biology, Brown University, 2Center for Computational Molecular Biology, Brown University, 3Department of Biology, Stanford University, 4Department of Anthropology, Stanford University, 5Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg
March 26, 2015 , Gateway Ballroom 2
Patterns of genetic variation are driven by human demographic history, but it remains unknown whether similar patterns are observed in linguistic traits such as phonemes - sound units that distinguish meaning between words in languages - on a global scale. Here we analyze, jointly and in parallel, phoneme inventories from 2082 worldwide languages and microsatellite polymorphisms from 246 worldwide populations. On a global scale, both genetic distance and phonemic distance between populations are signicantly correlated with geographic distance; also, languages in geographic proximity share more phonemes, whether or not they are closely related. We find the axes of greatest linguistic dierentiation within geographic regions correspond to axes of genetic dierentiation, suggesting that there is a relationship between human dispersal and phonemic variation. However, we do not find evidence that phonemes retain a signal of human expansion out of Africa. Further, although geographically isolated populations lose genetic diversity via genetic drift, we find that drift in phonemes across worldwide languages may not operate in the same manner: within a given geographic radius, languages that are relatively isolated are more susceptible to change, including gaining phonemes, than languages with many neighbors. Within a language family, modeling phoneme evolution along either a genetic or Bayesian cognate-based linguistic phylogeny predicts similar ancestral phoneme states to those predicted from ancient sources. These analyses join a long tradition of interdisciplinary studies underscoring that collaboration between geneticists, linguists, and anthropologists will deepen our understanding of human evolutionary history.