Genetic differentiation and gene flow between the Tunisian ovine breeds Barbarine and Western thin tail using random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis

Abstract

Sheep is an important livestock species of Tunisia. They contribute greatly to the food safety of the country and in the livelihood of a large number of small and marginal farmers and landless labourers engaged in sheep rearing. In this study, random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) analysis was used to assess the genetic difference and gene flow among two Tunisian sheep breeds (the Barbarine and the Western thin tail). A total of 62 bands were detected with an average of 7.75 bands per primer. The unweighted pair-group method with arithmetic average (UPGMA) and principal component analysis (PCA) showed a clear differentiation between the two studied breeds. Genetic differentiation coefficient (Gst) over all loci was 0.1922, the fixation index [Fst by Analysis of molecular variance (AMOVA)] was 0.308 (P<0.001), and the gene flow value (Nm) was 1.3102. It is clear from this study that Barbarine and Western thin tail breeds are completely distinct and that they show high and significant genetic differentiation. However, the level of gene migration between them is quite high and may lead eventually to the loss of breed’s purity.

Key words: Sheep, genetic differentiation, gene flow, RAPD-PCR.