Genetic Characterization of Cultured Tilapia in Fiji Using Allozymes and Random Amplified Polymorphic DNA

摘要

Fiji has recognized that appropriate breeding approaches are necessary if tilapia production is to continue to meet market demands To this end, genetic markers (allozymes and RAPDs) were developed to characterize the levels and patterns of genetic diversity in four cultured stocks of tilapia (Oreochromis niloticus (L) 'Chitralada', Oreochromis niloticus (L.) 'Israel' Oreochromis mossambicus (Peters) and a Red hybrid stock) in Fiji across four generations Although marker analyses revealed identical patterns of genetic relationship among the stocks, genetic diversity levels differed according to marker type Allozyme analysis revealed 50 loci of which 25 were polymorphic among the stocks cultured in Fiji. RAPD electrophoresis of seven random 10mer primers resulted in 95 scorable bands of which 58 putative loci were polymorphic among the stocks. Processes other than gene introgression among stocks have maintained relatively high levels of genetic diversity in most of the sampled stocks. Low levels of genetic diversity in O. mossambicus may preclude the use of this species in future breeding applications. This study is the first characterization of genetic diversity in any tilapia stock in the Pacific region and has provided a baseline for future genetic improvement and monitoring of the gene pools of cultured tilapia stocks.