Screening and identification of microsatellite markers associated with cold tolerance in Nile tilapia Oreochromis niloticus.

Tilapia is an important fish cultured in tropical and subtropical areas. Cold sensitivity limits the expansion of tilapia culture into colder regions of the world, and mass mortalities of cultured tilapia have been reported due to severe cold currents in winter. Since the late 1990s, several strains of Nile tilapia have been domesticated to improve the ability to adapt to low temperatures. Previous studies revealed that these varieties were more cold-tolerant than the founder population and overwintered naturally well in ponds in the west-south area of Guangdong Province. In this study, to develop tilapia strains with improved cold tolerance for breeding programs through marker-assisted selection, two microsatellite markers, UNH916 and UNH999, showed complete co-segregation with cold tolerance among the polymorphic microsatellite primers. Our results provide a foundation for identifying resistant gene(s) linked with these markers, as well as identifying simple sequence repeat markers associated with cold tolerance that can be used for maker-assisted selection programs in tilapia breeding to increase the growing range and productivity of tilapia aquaculture.