Polymorphism of the ND5/6 Gene in mtDNA of Strains of Nile Tilapia, Oreochromis niloticus

摘要

Restriction fragment length polymorphism (RFLP) analysis was conducted for the ND5/6 gene in mtDNA of different strains of Oreochromis niloticus. The size of ND5/6 gene fragment in mtDNA was about 2,393 ± 144 bp. The indices of haplotype diversity and nucleotide diversity of 0 niloticus were 0.6879 ± 0 0978 and 0.02659 ± 0.0978, respectively. The range of these strains was Sudan 78 > GIFT > Egypt 92 > Egypt 88. There were genetic differences among the four strains. The estimated phylogeny of the different strains indicated that. Egypt 88 was nearest to Egypt 92 and Sudan 78 was the most distant from the other strains. The results suggest that genetic bottlenecks and genetic introgression could be explained for mtDNA differentiation among strainsof O. niloticus. Sudan 78 possessed several unique haplotypes that might be a result of past mating with O. aureus females GIFT line also had several unique hapiotypes which was probably a result of its diverse ancestry. The predominant haplotype was also different for the GIFT line suggesting selection for dams that differ in origin from the other three strains.