Red-with-black-spots hybrid tilapia (progeny of Nile tilapia × pure-red Taiwanese red tilapia) were selected to backcross with the pure-red Taiwanese red tilapia, and selfcross of the pure-red Taiwanese red tilapia was as a control. Genetic variation of the progeny was analyzed with microsatellite DNA.
Results showed that the body coloration patterns for the progeny of positive and negative backcross group were black, blotched or red-with-black-spots, though number of black tilapia was scarce for the negative backcross, and the body length and body weight of the red-with-black-spots progeny were not significantly different (p＞0.05) with other patterns in the same group. The body coloration patterns for progeny of the control were pure red, blotched or red-with-black-spots, and on the body sizes, there was no significant difference among them.
Microsatellite DNA analysis of UNH123, UNH216, UNH222, UNH846, UNH849 and UNH860 locus showed that both mean observed heterozygosity (Ho) and mean expected heterozygosity (He) for progeny of the control were all smaller than those of the backcross groups, the former was with less genetic variation.