Utility of three mitochondrial gene regions to infer genetic variation of brood stock populations of Catla catla (Hamilton, 1822) in three Aquaculture Development Centers in Sri Lanka

Abstract

Catla catla is an economically important freshwater fish species in the carp family Cyprinidae and introduced species to Sri Lanka as a food fish. Their brood stock cultures are maintained at three Aquaculture Development Centers in Sri Lanka and fingerlings are produced for culturing purposes. This study was designed to investigate the utility of three mitochondrial gene regions to infer genetic variations of brood stock populations of Catla catla in three Centers. Samples were collected from brood stock populations of

Catla catla of three Aquaculture Iginiyagala and Udawalawa. From

Development Centers in Dambulla, each brood stock, 15 individuals were

randomly selected and DNA was extracted using a sample from the caudal fin of each individual. Partial DNA sequences of three mitochondrial gene regions; Cytochrome Oxidase II (COII) (920bp), Cytochrome b (Cyb) (354bp) and 12S rRNA (286bp), were recovered. Resulted sequences for each gene region were homogenous for all three centers indicating lack of genetic variation within and among populations. The percentage of A+T values were similar for COII and Cyb gene regions (58%) while it was 49% for 12S rRNA gene region. These results suggested that amplified section of the three mitochondrial gene regions in this study are highly conserved in nature and are not appropriate for population level study of Catla catla. It could be suggested that genetic information are needed to gather from more variable regions of mitochondrial and nuclear genome to analyze the population diversity levels of the above species.