Abstract

TORRES JARAMILLO, Julieta et al. Characterization of the red tilapia Oreochromis sp. through molecular markers RAPD. Acta Agron. [online]. 2010, vol.59, n.2, pp.236-246. ISSN 0120-2812.

Random amplified polymorphic DNA (RAPD) markers were used to study genetic diversity on red Tilapia (Oreochromis sp.) species collected from five fish farms located in the Valle del Cauca, Colombia and to determine the level of introgression from three parental species O. mosambicus, O. niloticus and O. aureus into local Oreochromis populations. from the 25 RAPD primers evaluated, eight were polymorphic and 109 banding patterns were observed, any of them were specific. The expected levels of heterozygosis (0.1964 to 0.2561) and genetic structure (G_st = 0.22) funded for Oreochrosmis sp. indicate high grade of polymorphism and genetic structuring. This results were observed following the analysis of molecular variance [AMOVA] (F_st = 0.268 (P <0.0001) and Multiple correspondence analysis (G_st = 0.040). The values of genetic similarity, the analysis of group, the analysis of multiple correspondence and the level of introgression, indicated that the differences in the introgression levels(P=0.0001) were significant). The low level of observed genetic differentiation among populations, could be the result of fish with the same genetic origin, whereas the high variation within populations can be displayed by handling practices and the pressure of selection to favor commercial phenotypes. The level of introgression among fish factories is significant for O. aureus, whereas species of O. niloticus and O. mosambicus are introgressed of similar way to the populations of Oreochromis sp.

Keywords : Oreochromis; mosambicus; O. niloticus; O. aureus; Cichlidae; DNA fingerprinting; RAPD; Genectic variation; Species differentation.

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