Inferring patterns of folktale diffusion using genomic data

Abstract

We find that a model of cultural diffusion predicted by isolation-by-distance alone is not sufficient to explain the observed patterns, especially at small spatial scales (up to ∼4,000 km). We also provide an empirical approach to infer presence and impact of ethnolinguistic barriers preventing the unbiased transmission of both genetic and cultural information. After correcting for the effect of ethnolinguistic boundaries, we show that, of the alternative models that we propose, the one entailing cultural diffusion biased by linguistic differences is the most plausible. Additionally, we identify 15 tales that are more likely to be predominantly transmitted through population movement and replacement and locate putative focal areas for a set of tales that are spread worldwide.cultural diffusion | demic diffusion | whole-genome sequences | folktales | Eurasia A dvances in DNA sequencing have opened new ways for exploring the demographic histories of human populations and the relationship between patterns of genetic and cultural diversity around the world. Newly available genome-wide evidence enables us to go beyond the use of linguistic relationship as a measure of common ancestry (1-3) and offers unprecedented support for studying the mechanisms underlying the transmission of cultural information over space and time (4-11) as well as the coevolution of genetic and cultural traits (12-18) across populations.A key question for research in this area concerns the extent to which patterns of cultural diversity documented in the archaeological and ethnographic records have been generated by demic processes (i.e., the movement of people carrying their own cultural traditions with them) or cultural diffusion (i.e., the transfer of information without or with limited population movement/replacement) (6,19,20). Before tackling this question, however, it is critical to note that demic processes and cultural diffusion are not mutually exclusive conditions but rather, are opposite extremes of a continuous gradient, with intermediate and composite positions that more accurately represent empirical reality.A broadly adopted null model of cultural diffusion draws on the expectation that selectively neutral variants would form geographic clines produced over time by isolation-by-distance (IBD) processes (21). Under an IBD model, individuals or groups that are spatially closer to each other are expected to be more similar than individuals or groups that are located farther apart. A positive correlation between cultural dissimilarity and geographic distance between samples is, therefore, used to infer processes of cultural transmission of nonadaptive information without population replacement (8,17). However, observed genetic distance is the composite result of serial founder events, longterm IBD, and subsequent migratory events, which imply recent movement and resettling of people (22). A higher correlation between genetic distance and cultural dissimilarity than between culture and geography has, therefore, been proposed as a way...

Cultural evolution of music

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Reconciling material cultures in archaeology with genetic data requires robust cultural evolutionary taxonomies

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A quantitative approach to the study of Neolithic projectile points from south‐eastern Arabia

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