Genetic analysis of Til-Aqua’s silver strain made

Characterizing the genetic structure of introduced nile tilapia (oreochromis niloticus) strains in Tanzania using double digest rad sequencing

A genetic analyses of the Silver strain of Til-Aqua has been made by an international group of researchers (See link above). This research revealed a higher genetic variation in the case of animals that originated from selective breeding programs like the YY- strain from Til-Aqua. The research also proved that the genetic inbreeding coefficient (Fis) of the examined strains was the lowest for the fish from Til-Aqua. This is due to the fact that the NMT is always a combination of two genetic strains, a mixed sex line and the YY-line. This combination results in a so called heterosis effect.

The researchers also concluded that a higher genetic distance was found between the strain from the Netherlands (silver-YY strain) with the strains from Uganda (Fst, 0.38–0.44), compared with the strains from Thailand (Fst, 0.26–0.30). The researchers also concluded that ”regarding the silver-YY strain from Netherlands, both STRUCTURE and DAPC suggested the existence of an isolated cluster”. This is in accordance with the fact that the strains of Til-Aqua are under their own selection program for over 20  years, and that no other genetics have entered the farm since the original imports. This has resulted in their own geographical isolated genetic cluster.