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Edited by Simon A. Levin, Princeton University, Princeton, NJ, and approved October 13, 2017 (received for review April 27, 2017)
Significance
Associations between genes and languages occur even with sustained migration among communities. By comparing phylogenies of genes and languages, we identify one source of this association. In traditional tribal societies, marriage customs channel language transmission. When women remain in their natal community and men disperse (matrilocality), children learn their mothers’ language, and language correlates with maternally inherited mitochondrial DNA. For the converse kinship practice (patrilocality), language instead correlates with paternally inherited Y chromosome. Kinship rules dictating postmarital residence can persist for many generations and determine population genetic structure at the community scale. The long-term association of languages with genetic clades created by kinship systems provides information about language transmission, and about the structure and persistence of social groups.
Abstract
Languages are transmitted through channels created by kinship systems. Given sufficient time, these kinship channels can change the genetic and linguistic structure of populations. In traditional societies of eastern Indonesia, finely resolved cophylogenies of languages and genes reveal persistent movements between stable speech communities facilitated by kinship rules. When multiple languages are present in a region and postmarital residence rules encourage sustained directional movement between speech communities, then languages should be channeled along uniparental lines. We find strong evidence for this pattern in 982 individuals from 25 villages on two adjacent islands, where different kinship rules have been followed. Core groups of close relatives have stayed together for generations, while remaining in contact with, and marrying into, surrounding groups. Over time, these kinship systems shaped their gene and language phylogenies: Consistently following a postmarital residence rule turned social communities into speech communities.
Footnotes
↵1J.S.L and C.A. contributed equally to this work.
- ↵2To whom correspondence should be addressed. Email: jlansing{at}ntu.edu.sg.
Author contributions: J.S.L., C.A., G.S.J., S.S.D., L.Y.C., T.B., H.S., and M.P.C. designed the research; C.A., G.S.J., E.G.G., S.T., S.S.D., and N.N.C. performed analyses; and J.S.L., C.A., G.S.J., and M.P.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1706416114/-/DCSupplemental.
- Copyright © 2017 the Author(s). Published by PNAS.
This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).
Kinship structures channel language transmission
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- Anthropology
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