GENETIC DIVERSITY OF MITOCHONDRIAL DNA (MTDNA) D-LOOP SEQUENCES IN SIX IMPROVED TROPICALLY ADAPTED CHICKEN BREEDS (iTABS)

Résumé

Improved tropically adapted chicken breeds (iTABs) are characterized as dual purpose, low-input high-output birds suitable for smallholder poultry (SHP). A 592-bp of mitochondrial DNA (mtDNA) D-loop region of 77 iTABs from six populations was amplified to assess the genetic differentiation of six iTABs introduced to smallholder poultry farmers in Imo State, Nigeria by the African Chicken Genetic Gains (ACGG) project. The specific objectives were to determine the level of polymorphism among and within the breeds, origin, phylogenetic relationship and evolutionary distance between and among these breeds. The haplotype diversity and nucleotide diversity of the iTABs were 0.80±0.025 and 0.391±0.013, respectively. 14 haplotypes were identified from 62 polymorphic sites. These haplotypes clustered into three clades with 99.7 % of the total maternal genetic variations occurring within population. Sasso and Shika Brown had the least (0.385) genetic distance. The results indicate the existence of three distinct maternal lineages from Southeast Asia, Indian subcontinent and Southwest China evenly distributed among the iTABs. The high genetic diversity observed within population can be utilized for the long term genetic improvement and stabilization of the breeds.