Flow cytometric analysis of genome size of Oreochromis niloticus and O. aureus and their interspecific hybrid

Abstract

Srikandi tilapia, a hybrid resulting from an interspecific cross between female Oreochromis niloticus and male O. aureus, has shown advantages in farming performance. It shows higher productivity in high salinity aquaculture environment than that of both parental lines. From genetic point of view, organismal phenotypes, to some extent might be affected by its genome size or cellular DNA content. This study was aimed to identify the genome size of these two species along with their hybrid. 75 individuals representing three groups, namely two parental lines and its hybrid were sampled and measured for their DNA content by flowcytometry. The mean (±SD) DNA content of O. aureus (1.271 ± 0.0022 pg) was higher but was not statistically significantly different (P>0.0175) from that of the O. niloticus (1.261 ± 0.0022 pg). The mean (±SD) DNA content of the hybrid (1.263±0.001) was in between and was not significantly different (P>0.05) from both parental species. Individual variation of DNA content within species was lower than those between species. No significant difference was observed in DNA content between male and female within the respective groups.