The study is about matrilineal systems, where descent is traced along female lines. Matrilineal systems are relatively rare in human populations, and previous research has discussed the rarity and apparent instability of matriliny. The study aims to study the evolution of descent systems on a worldwide scale. The study tests for significant associations between matriliny and numerous cultural traits that have been theoretically associated with its stability or loss, such as subsistence strategy, animal domestication, mating system, residence pattern, wealth transfer, and property succession. Additionally, by combining genetic and linguistic information to build a global supertree that includes 16 matrilineal populations, the study also performs phylogenetically controlled analyses to assess the patterns of correlated evolution between descent and other traits.

While not mechanically related, the transmission of genes and the transmission of languages are both mediated by culture. For example, in societies where marriage outside the language group is common, matrilocal residence practices may result in the preferential conservation of the mother’s language(s), as well as the development of distinct mtDNA haplogroups throughout a region. In this study, the authors use single nucleotide polymorphism (SNP) data from 130 culturally distinct populations to assess the correlation between genetic distance and linguistic distance, while controlling for various cultural and geographic factors (in other words: when populations are more genetically dissimilar, do they also tend to be further apart linguistically?). Results suggest that while the often-referenced idea of sex-based transmission of language is not universally predictable, linguistic distance almost always tends to correlate positively to both spatial and mitochondrial genetic variation.