Parallel Trajectories of Genetic and Linguistic Admixture in a Genetically Admixed Creole Population

Abstract

Joint analyses of genes and languages, both of which are transmitted in populations by descent with modification-genes vertically by Mendel's laws, language via combinations of vertical, oblique, and horizontal processes [1-4]-provide an informative approach for human evolutionary studies [5-10]. Although gene-language analyses have employed extensive data on individual genetic variation [11-23], their linguistic data have not considered corresponding long-recognized [24] variability in individual speech patterns, or idiolects. Genetically admixed populations that speak creole languages show high genetic and idiolectal variation-genetic variation owing to heterogeneity in ancestry within admixed groups [25, 26] and idiolectal variation owing to recent language formation from differentiated sources [27-31]. To examine cotransmission of genetic and linguistic variation within populations, we collected genetic markers and speech recordings in the admixed creole-speaking population of Cape Verde, whose Kriolu language traces to West African languages and Portuguese [29, 32-35] and whose genetic ancestry has individual variation in European and continental African contributions [36-39]. In parallel with the combined Portuguese and West African origin of Kriolu, we find that genetic admixture in Cape Verde varies on an axis separating Iberian and Senegambian populations. We observe, analogously to vertical genetic transmission, transmission of idiolect from parents to offspring, as idiolect is predicted by parental birthplace, even after controlling for shared parent-child birthplaces. Further, African genetic admixture correlates with an index tabulating idiolectal features with likely African origins. These results suggest that Cape Verdean genetic and linguistic admixture have followed parallel evolutionary trajectories, with cotransmission of genetic and linguistic variation.

Sex-biased admixture and assortative mating shape genetic variation and influence demographic inference in admixed Cabo Verdeans

“…CC-BY 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprint this version posted December 15, 2020. ; https://doi.org/10.1101/2020.12.14.422766 doi: bioRxiv preprint Previous investigations of genetic ancestry in Cabo Verde 34,35,37 have shown extensive admixture in the archipelago and differences in the mean African genetic ancestry across islands, which may reflect the differences in the settlement history and suggest restricted gene flow between islands. Using genome-wide SNP data from 563 individuals spanning the three settlement stages of Cabo Verde, we integrate several population genomic approaches to infer the sexspecific demographic history of the last ~20 generations since founding, and consider the potential biases of nonrandom mating on common inference methods.…”

Complex genetic admixture histories reconstructed with Approximate Bayesian Computations

“…We excluded from our sample set, individuals previously identified to be more closely related than first-degree cousins in the four populations separately (VERDU et al . 2017).…”

Unraveling African diversity from a cross‐disciplinary perspective

“…On both sides of the African continent, recent mass migrations contributed to one of the humanity's darkest chapters, the slave trade. Along the west African coast, the transatlantic slave trade impacted the demographic history of numerous populations, for example, the population history of Cape Verdean Kriolu speakers . The Indian Ocean slave trade network, along the east African coast, mainly impacted African islands from southeastern Africa, for example, the genetic landscape of the Malagasy population …”

“…Along the west African coast, the transatlantic slave trade impacted the demographic history of numerous populations, 22,30 for example, the population history of Cape Verdean Kriolu speakers. 31 34 This consortium also encourages the formation of intracontinental collaborations and development of training programs and facilities necessary to lead high-quality genomics and biomedical research in Africa. 35 One of the H3Africa projects, the AWI-Gen study, was designed to determine genetic and environmental contributions to cardiometabolic diseases and related traits in African groups.…”