Herança genética materna dos principais grupos étnicos da Nigéria

Abstract

Africa is the birthplace of modern humans, being the region of the world that today houses the highest genetic, cultural and ethnic diversities. Therefore, an increasing number of studies focusing on African populations have been carried out in the fields of population genetics and anthropology. Part of this diversity can be seen in Nigeria (also known as the “Giant of Africa”), which is the most populous country in the continent and the seventh most populous country in the world, with about 250 ethnolinguistic groups spread across its territory. Specific features of the mitochondrial DNA, such as lack of recombination, high mutation rates and uniparental transmission, have made this molecule increasingly useful in a broad field of applications, such as human evolution, population genetics and forensic studies. In addition, studies on the genetic diversity among human populations are increasingly widespread, arousing the interest of those seeking information about their ancestry, such as the most likely place of origin of their ancestors, before the Black Diaspora. The present work aimed to characterize the genetic diversity of the maternal lineages in three main ethnolinguistic groups in Nigeria. Herein, we also explored whether the genetic variability found allows the differentiation of populations. Besides, we also intended to increase data in forensic databases, regarding the maternal ancestry of African populations. Samples belonging to 285 males were investigated for the mitochondrial DNA control region. High haplotype diversity values were found in the three groups: Hausa (HD = 0.9996 ± 0.0024), Yoruba (HD = 0.9992 ± 0.0013) and Igbo (HD = 0.9984 ± 0.0017). Most haplotypes found belong to macrohaplogroup L (98%), characteristic of Sub-Saharan African populations. Four non-L haplogroups were also found, which are characteristic of North Africa and Eurasia, two of them were present in the Hausa group. The comparison of the three ethnic groups in Nigeria did not show statistically significant differences (p ≥ 0,5), with high non-differentiation probabilities and negative FST values between population samples. The genetic distances calculated between Nigerian and other African populations showed a proximity of the three ethnolinguistic groups with populations from countries geographically close to Nigeria, even from different linguistic families. Such results reinforce the persistence of a social/institutional pattern that shaped the relationships between populations, as well as, the homogenization of the maternal lineages of the populations in this region of Africa. This homogeneity reflects a higher female migration, probably motivated by patrilocality practices.