Contrasting Maternal and Paternal Histories in the Linguistic Context of Burkina Faso

Abstract

Burkina Faso is located in the heart of West Africa and is a representative of the local structured patterns of human variability. Here, different cultures and languages are found in a geographic contiguity, as a result of several waves of migration and the succession of long- and short-term empires. However, historical documentation for this area is only partial, focusing predominantly on the recent empires, and linguistic surveys lack the power to fully elucidate the social context of the contact-induced changes. In this paper, we report Y-chromosomal data and complete mtDNA genome sequences for ten populations from Burkina Faso whose languages belong to two very distantly related branches of the Niger-Congo phylum, the Gur and Mande language families. In addition, two further populations, the Mande-speaking Mandenka from Senegal and the Yoruba from Nigeria, were included for regional comparison. We focus on the different historical trajectories undergone by the maternal and paternal lineages. Our results reveal a striking structure in the paternal line, which matches the linguistic affiliation of the ethnolinguistic groups, in contrast to the near-complete homogeneity of the populations in the maternal line. However, while the ancient structure along the linguistic lines is apparent in the Y-chromosomal haplogroup affiliation, this has clearly been overlain by more recent migrations, as shown by significant correlations between the genetic distances based on Y chromosome short tandem repeats and geographic distances between the populations, as well as by the patterns of shared haplotypes. Using the complete mtDNA sequences, we are able to reconstruct population size variation in the past, showing a strong sign of expansion in the concomitance with the Holocene Climate Optimum approximately 12,000-10,000 years ago, which has been suggested as the cause of the spread of the Niger-Congo phylum in the area. However, subsequent climatic fluctuations do not appear to have had an impact on the demography of the inhabitants of West Africa, probably reflecting the adaptive advantages of cultural innovations, such as pastoralism and agriculture.

The influence of clan structure on the genetic variation in a single Ghanaian village

“…Our result of clan specific Y-chromosomal lineages together with results of de Filippo et al 9 indicate a scenario where several patrilineally related genetic lineages constitute a ‘tribe'. The fact that we find similar patrilineal lineages across West Africa 10 raises the intriguing possibility that many ethnic groups (or ‘tribes') or even ethnolinguistic groups 14 that identify themselves as homogenously related entities, consist of the same small number of closely related genetic lineages. The consequence is that the relative frequency of these Y-chromosomal lineages ( i.e ., the Y-haplogroups) within such constructed groups could be caused entirely by the relative contributions of distinct clans within an ethnic group.…”

“…3 For West Africa, however, there are some detailed genetic studies on smaller scales. 9, 10, 11, 12, 13, 14 For instance, Coelho et al 13 reveal strong patterns in the genetic structure of human populations on the small island of Sao Tomé that were influenced by spatial- and temporal-specific events. Ottoni et al 15 show strong founder effects and drift that have resulted in very different paternal lineages in two Libyan villages.…”

MtDNA analysis of global populations support that major population expansions began before Neolithic Time

“…Φ ST distances between populations in current study or previous analysis14213355565758596061 were calculated in Arlequin 3.11 also via coding regions, and plotted in PAST 1.8562 with a non-metric multidimensional scaling method (see Figure S1), showing that populations in each continent were clustered together.…”

Ancestral Stories of Ghanaian Bimoba Reflect Millennia-Old Genetic Lineages

“…Unlike the male generation time, in Sub-Saharan Africa the generation time of 25 years (or even lower in the Ghanaian study region) is better suited for generation time estimate of mtDNA markers, markers inherited uniparentally by women. Estimates from mtDNA by Barbieri et al [31] in neighbouring Burkina Faso of an ancient demographic expansion using female generation time of 25 years led to a dating, from 9000 to 14000 ya. This coincides with our estimate of Y-STR data in males, suggesting that we observe a related expansion event in our Ghanaian data.…”