Assessment of the Genetic Diversity and Population Structure of Local Chickens of Five Gabonese Ecotypes Using 28 of the 30 Microsatellite Markers Recommended by the FAO

Sylvère Mboumba, Landry Mombo, Richard Habimana, Christian Keambou, Anique Gbotto, Sarah Osama, Pauline Asami and Nasser Yao

Background and Objective: The management of livestock biodiversity has become an important issue for the international scientific community. For this purpose, we assessed genetic variation in local chicken (Gallus gallus) populations from five regions of Gabon. Materials and Methods: A total of 28 microsatellite markers were used to genotype 194 individuals, including one commercial line (Isa Brown) that was assessed for possible introgression into local gene pools. A total of 292 alleles were revealed in the whole population with an average of 10.429 alleles per locus. Results: The observed heterozygosity rate was 0.484, 0.472, 0.495, 0.483 and 0.495 for Franceville, Libreville, Makokou, Mouila and Oyem, respectively. These values are below the expected heterozygosity for each locality (p<0.05). This resulted in a positive inbreeding coefficient in the local chicken populations and a negative coefficient in the commercial chickens. Wright's F-statistics (Fit = 0.216; Fis = 0.110; Fst = 0.123) suggesting moderate differentiation of individuals. Analysis of molecular variance revealed that 83% of the total genetic diversity was attributed to within-population variation and the remaining 5 and 12% were attributed to differentiation between regions and individuals, respectively. The pairwise genetic distances of the populations were very small (0.008≤GD≤0.017) between local populations and very large (0.833≤GD≤0.884) when comparing the local populations to the commercial chicken population. The analysis of the structure of the whole population revealed three genetic entities. These results showed that the study population has a satisfactory genetic diversity and a low level of introgression of exotic genes into the identified local gene pool. Conclusion: This genetic diversity constitutes an important basis for the implementation of conservation and genetic improvement programmes for local chickens in Gabon.

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