Exploring correlations in genetic and cultural variation across language families in northeast Asia

Abstract

Culture evolves in ways that are analogous to, but distinct from, genomes. Previous studies examined similarities between cultural variation and genetic variation (population history) at small scales within language families, but few studies have empirically investigated these parallels across language families using diverse cultural data. We report an analysis comparing culture and genomes from in and around northeast Asia spanning 11 language families. We extract and summarize the variation in language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations. We find that grammatical structure correlates with population history (genetic history). Recent contact and shared descent fail to explain the signal, suggesting relationships that arose before the formation of current families. Our results suggest that grammar might be a cultural indicator of population history while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human history.

Fig. 1.. Geographic areas of 14 languages/populations.

Because some of the areas overlap in space, they are plotted in two separate maps.

Fig. 2.. Neighbornet networks of the populations based on dimensionality-reduced distance matrices in SNPs, lexicon, grammar, phonology, and music (see Materials and Methods).

Colors indicate language families: Selkup and Nganasan belong both to Uralic; Even and Evenki to Tungusic; and Koryak and Chukchi to Chukotko-Kamchatkan.

Fig. 3.. RDA between five pairs of factors (lexicon, genetics, grammar, music, and phonology).

Variance in the response explained by each explanatory variable; * indicates a significant association (P ≤ 0.05).

Fig. 4.. Partial RDA controlling for spatial autocorrelation and linguistic inheritance: Densities of the difference between observed and permuted adjusted R² (z-normalized) in the partial RDA.

Numbers right to the dashed line show the proportion of samples with a difference of at least one SD. Gray shading reflects the KLD between the observed and permuted adjusted R². The KLD is transparent for associations where the z-normalized difference is negative for more than 50% of the samples.