PHYLOGENETIC ANALYSIS ON FOUR SPECIES OF TILAPIA (Oreochromis niloticus, Tilapia zilli, Sarotherodon galilaeus, Sarotherodon melanotheron) IN NIGERIA

Abstract

An investigation into evolutionary history of four species of Tilapia species was carried out as a taxonomy tool to relate most tilapia species found within the Nigerian waters. These species are (Oreochromis niloticus, Tilapia zilli, Sarotherodon galilaeus, Sarotherodon melanotheron). Blood samples from the four species of tilapia were collected and preserved on Fast Technology for Analysis (FTA) cards for DNA extraction and PCR amplification. The various nucleotide sequences of the four Tilapia species found in the Mitochondria D-loop region were copied and aligned with the use of BioEdit and Mega 6.0 softwares. Three phylogenetic trees were drawn to show the evolutionary relationship amongst the four species of tilapia. The results indicated that Sarotherodon galilaeus and Sarotherodon melanotheron are sister texa and share a common ancestor with Oreochromis niloticus. Tilapia zilli is an out group which is the most distantly related to the three species (Oreochromis niloticus, Sarotherodon galilaeus Sarotherodon melanotheron). Tilapia zilli (Israel) and Tilapia zilli are sister texa and share a common ancestor in Tilapia sparmanii. The study also revealed ancestry relationship among other species of fish Cyprinus caprio and Clarias gariepinus formed a clade with the three tilapia species (Tilapia zilli, Tilapia zilli (Israel) and Tilapia sparmanii), which share an unknown but common ancestor.