Two Rapd-scar Markers in New Gift Nile Tilapia (oreochromis Niloticus) Implication for Selection Tracking and Strains Identification

The NEW GIFT Nile tilapia is a national certificated new strain produced through 14 years and 9 generations selection from the base strain of GIFT Nile tilapia. From NEW GIFT Nile tilapia two strain-specific RAPD bands namely S304 and S36 were identified from the amplified bands of 50 and 80 10bp-oligo-nucleotide random primers separately after gel extraction cloning and sequencing of the strain-specific RAPD bands two pairs of primer(20 base for forward primer and 21 base for reverse primer) was designed according to sequence information, then PCR amplification was carried out in NEW GIFT Nile tilapia and base strains and other 7 farmed strains. For the first primer, one 553bp SCAR was amplified showed a 86.7% appearing frequency in NEW GIFT Nile tilapia but only 17% in base strain. This marker has been used as a specific monitor marker for tracking of selection. For the second primer, one 558bp SCAR was amplified showed a 91.4% appearing frequency in NEW GIFT Nile tilapia and 0-70% in other 7 strains. This marker has been used as a specific molecular marker for identification of Nile tilapia strains. The development of these two markers indicated that the frequency of some alleles related with economically important traits might increase during selection.