GENETIC DIVERSITY AND PHYLETIC EVOLUTION OF NORTHEAST NIGERIAN INDIGENOUS CHICKEN POPULATION BY MTDNA SEQUENCE

Résumé

Nigerian indigenous chicken (NIC) breeds are geographically widespread, with more than 12 breeds listed as national genetic resources. However, NIC breeds are facing declining population and germplasm degeneration as a result of lots of commercial chicken strains been introduced. In this study, the genetic diversity and phylogenetic structure of Northeast (NE) Nigerian chicken were investigated based on mitochondrial DNA D-loop sequences of 397 base-pair in length. A total of 38 individuals were examined, and 8 haplotypes were observed in 9 polymorphic sites (5 singleton and 4 parsimony-informative) with high A+T content (63.46%) compared to G+C content (36.54%). The haplotype and nucleotide diversity indices were 0.588 and 0.002 respectively indicating relatively low genetic variability. Phylogenetic analysis and a star-like pattern median joining (MJ) network revealed that these individuals were grouped into one distinct genetic clade (cluster A). A non-statistically
significant Tajima (D’s) and Fu (F’s) values of -1.718 and -3.964 respectively, and sum of squared deviation (ssd: 0.007) and Harpending‟s raggedness index (rag: 0.105) suggested no rapid expansion event that occurred in NE Nigerian. This study concluded that Northeast Nigerian chicken has relatively high genetic variability, but, low genetic diversity which could be exploited for efficient breeding selection and genetic resources conservation.