Abstract
Background: There are over 2000 genetically diverse ethnolinguistic groups in Africa that could help decipher human evolutionary history and the genetic basis of phenotypic variation. We have analysed 298 genomes from Niger Congo populations from six sub Saharan African countries (Uganda, Democratic Republic of Congo, Cameroon, Zambia, Ivory Coast, Guinea) and a Nilo Saharan population from Uganda. These samples were collected as part of the TrypanoGEN consortium project http://www.trypanogen.net. Results: The population genetic structure of the 298 individuals revealed four clusters which correlated with ethnolinguistic group and geographical latitude, that is, West African Niger-Congo A, Central African Niger Congo, East African Niger-Congo B and the NiloSaharan. We observed a spatial distribution of positive natural selection signatures in genes associated with AIDS, Tuberculosis, Malaria and Human African Trypanosomiasis among the TrypanoGEN samples. Having observed a marked difference between the NiloSaharan Lugbara and Niger Congo populations, we identified four genes [APOBEC3G, TOP2B, CAPN9, LANCL2, (iHS -log p > 3.0, Rsb -log p > 3.0, Fst > 0.1 Bonferroni p > 1.8x10e4)], which are highly differentiated between the two ethnic groups and under positive selection in the Lugbara population. Conclusion: The signatures that differentiate ethnically distinct populations provide information on the specific ecological adaptations with respect to disease history and susceptibility/ resistance; as demonstrated in this study where APOBEG3G is believed to be involved in the susceptibility of the Nilo Saharan Lugbara population to Hepatitis B virus infection.
