Search

Immune genes are under acute selective pressure in order to resist pathogenic attacks. It is not really clear the type of selective force that acts on immune genes because of diverse pathogen load and host population density, so this experiment studied the selective force acting on exon 3 of IRF-5 gene in Nigerian indigenous chickens. DNA was extracted from 90 Nigerian indigenous chickens and exon 3 of IRF-5 gene was sequenced. The region was tested for deviation from neutrality using DnaSP. The Mean non-synonymous substitutions per non-synonymous site (dN) and mean synonymous substitutions per synonymous site (dS) were calculated to predict likely selective force/event acting on the region using HyPhy software implemented inside MEGA6 software. All the test of neutrality indices obtained for exon 3 of IRF-5 gene in Nigerian indigenous chickens were greater than 1 except Tajima’s D value of normal feather chickens (0.93) and Fu’s Fs value of naked neck chickens (0.71). The dN of 0.00 and negative dS were estimated for exon 3 of IRF-5 gene in all the three genotypes. This study therefore concluded that purifying selective forces are acting on exon 3 of IRF-5 gene in Nigerian indigenous chickens. Keywords: Chickens, co-evolution, immunity, pathogens, selection.

In this study, the maternal genetic diversity and phylogenetic relationship of Nigerian duck populations were assessed. A total of 591 base pair fragment of the mitochondrial DNA (mtDNA) D-loop region of 87 indigenous ducks from two populations in Nigeria were analyzed. Seven haplotypes and 70 polymorphic sites were identified. The mean haplotypic and nucleotide diversity were found to be 0.381±0.058 and 0.315±0.155 respectively. The phylogeny revealed two divergent haplotype clades, suggesting two possible maternal lineage in Nigerian duck population, with the most commonly shared haplotype belonging to Mallard ducks ( Anas platyrhynchos ). Genetic variation within and between populations accounted for 63.32% and 36.68% of the total genetic variation respectively. This study concluded that there was relatively high genetic diversity and differentiation, thus, this information will probably pave way for further evaluation studies, preservation and improvement of Nigerian ducks as genetic resources. Keywords : Genetic Diversity, MtDNA, Nigerian duck, phylogeny