Linking between genetic structure and geographical distance: Study of the maternal gene pool in the Ethiopian population

Abstract

Background The correlation between genetics and geographical distance has already been examined through the study of the dispersion of human populations, especially in terms of uniparental genetic markers.

Aim The present work characterises, at the level of the mitochondrial DNA (mtDNA), two new samples of Amhara and Oromo populations from Ethiopia to evaluate the possible pattern of distribution for mtDNA variation and to test the hypothesis of the Isolation-by-Distance (IBD) model among African, European and Middle-Eastern populations.

Subjects and methods This study analysed 173 individuals belonging to two ethnic groups of Ethiopia, Amhara and Oromo, by assaying HVS-I and HVS-II of mtDNA D-loop and informative coding region SNPs of mtDNA.

Results The analysis suggests a relationship between genetic and geographic distances, affirming that the mtDNA pool of Africa, Europe and the Middle East might be coherent with the IBD model. Moreover, the mtDNA gene pools of the Sub-Saharan African and Mediterranean populations were very different.

Conclusion In this study the pattern of mtDNA distribution, beginning with the Ethiopian plateau, was tested in the IBD model. It could be affirmed that, on a continent scale, the mtDNA pool of Africa, Europe and the Middle East might fall under the IBD model.

Keywords:

• mtDNA
• Ethiopia
• Isolation-by-Distance
• Horn of Africa

Acknowledgements

We thank F. Chiabrera, P. Stoppato, and L. Simonetti, members of the ‘Istituto per la Cooperazione Universitaria’, for the help they provided during the fieldwork. We are also indebted to G. Roro, Director of the Arssi Regional Health Department, for his help in solving logistic problems and to L. B. Anderson for linguistic revision of the manuscript. This project was supported by the ‘Ministero dell’Istruzione, Università e Ricerca’ (MIUR), through grants allotted to G.F.D.S., and by the CNR Special Project, ‘Cultural Heritage’, allotted to O.R. (prot. num. 96.01168.PF36- 97.00689.PF36).

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.