NEW YORK – An international team led by investigators in Switzerland and Japan has detected ties between population genetics and language patterns in northeast Asia, particularly between populations with similar grammatical structures, hinting that grammar may serve as a marker for ancient relationships between populations.
"The modern distribution of linguistic structures … is shaped by contact in deep prehistory much more than we thought," co-senior and co-corresponding author Balthasar Bickel, a comparative language science researcher at the University of Zurich and investigator with the Center for the Interdisciplinary Study of Language Evolution in Zurich, explained in an email.
For a study published in Science Advances on Wednesday, the researchers brought together new and published array-based genotyping profiles for individuals from more than a dozen populations in northeast Asia, spanning 11 language families or groups. By analyzing the SNP profiles alongside available grammatical, phonology, lexical, and musical patterns ranging from song structures to performance styles across the populations considered, they saw significant ties between genetics and grammatical structure that did not extend to broader cultural features.
"Northeast Asia provides a useful test region because it contains high levels of genetic and cultural diversity, including a large number of small language families or linguistic isolates," the authors explained, noting that "while genetic and linguistic data throughout much of the world have been published, northeast Asia is the only region for which published musical data allow direct matched comparison of musical, genetic, and linguistic diversity."
For their study, the investigators focused on genotyping profiles for individuals from 14 populations in the northeast Asian region, including 22 individuals from the Nivkh population on Russia's Sakhalin Island who were genotyped for the first time for the study.
Together with available data on language features, phonology, musical performances, and other cultural traits, the genetic profiles made it possible to search for relationships between SNP-based principal component clusters and each of the individual cultural traits considered.
While populations did not all share the same set of cultural features, the team found that population genetics and grammar most closely coincided with one another, and appeared to reflect early, ancestral relationships between populations in the region.
"[O]ur findings are compatible with a scenario where specific traits (e.g., word order) evolved rapidly within families but were repeatedly copied and readapted," the authors suggested, "yielding a relatively uniform profile over a prehistoric period that mirrors the genetic network of the same period."
In contrast, the authors noted that genetics and grammatical structure did not always line up with the presence or absence of other cultural markers. Instead, some genetically distinct populations shared musical stylings, phonology, or other cultural traits, while other genetically similar groups had discordant cultural practices.
"Our results suggest that grammatical structure may reflect population history more closely than other cultural (including lexical) data, but we also find that different aspects of genetic and cultural data reveal different aspects of our complex human histories," the authors wrote, suggesting that "cultural relationships cannot be completely predicted by human population histories."