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Abstract
Abstract
This study was conducted on samples collected in the years 2002, and 2003 from three wild environments in the Suez Canal Zone. The study included 2500 fish specimens involving 4 species Oreochromis niloticus, Oreochromis aureus, Sarotherodon galilaeus and Tilapia zilli. Morphometric parameters included total length (TL), standard length (SL), body depth (BD), body thickness (BT), head width (HW) and head length (HL). RAPD PCR using 10 decamers primers was conducted on representative samples from the four species collected from the three different environments in the Suez Canal Zone (ZF, ZB, ZS, NF, NB, AF, AB, GF, and GB). All data were analyzed using DFA or PCA. The major components of variance for morphometric parameters accounted for 73.45% of the variance based on the first function. 340 RAPD markers were identified in the 9 populations. The RAPD patterns generated by primers 1 and 6 were together sufficient to distinguish the 9 tilapia populations. The discrimination indices of primers 1 and 6 were 0.89 and 0.83 respectively. The major components of variance for RAPD markers accounted for 72 % of the variance. The use of two way clustering revealed that certain RAPD markers are associated with adaptation of the genomes to salinity or brackish water conditions. These markers will be useful in future experiments on MAS breeding for tolerance to salinity in Nile Tilapia.
Keywords: RAPD-PCR, Morphometrics, Multivariate analysis, Salinity.