
Genetic diversity in tilapia populations in a freshwater reservoir assayed by randomly amplified polymorphic DNA markers
a b s t r a c t
Genetic variation in fish stocks decreasing due to water pollution in the freshwater rivers, streams and
canals. The objective of this study was to determine the genetic diversity and polymorphism in
Oreochromis niloticus collected from the Wadi Hanefah Riyadh, Saudi Arabia by using RAPD-PCR. Total
thirty fish specimens were harvested from each of four pre-determined locations of the reservoir which
were designated as H1, H2, H3, and H4. Five random decamer primers were used to assess the diversity in
the stock of O. niloticus. In this fish stock 48 bands were polymorphic and 12 were monomorphic. The
maximum polymorphism (100%) was recorded in the fish samples procured from H4, followed by
88.75, 87.33 and 76.12% of the tilapia collected from H3, H2, and H4, respectively. Nei’s genetic distance
value was ranged as 0.0005 to 0.1006. Maximum and minimum genetic distance was recorded as 0.1006
and 0.005 in tilapia harvested from H1 and H2 locations. Average heterozygosity was ranged from 0.3009
to 0.3744. This information about the genetic polymorphism of O. niloticus may be used by the concerned
authorities to evolve strategies to conserve the diversity of tilapia in the country.