Abstract

This study aimed at investigating growth-related, EST-derived microsatellite markers in Nile tilapia (O. niloticus). The link between alleles and genotypes of these makers was particularly examined, as well as the growth performances of the samples of offspring produced from the broodstocks of 5 different fishery stations in Thailand. A total of 25 families of offspring were reared to observe the growth performance for a period of 83 days. Fish samples in this study were divided into two categories according to average body weight: fast (+SD) and slow (-SD) growth. Then, the fins of the fish samples were employed to perform DNA analysis. From the fast and slow growth evaluations, 3 families, namely F1, F24 (from Chumphon) and F11 (from Petchaburi), were chosen for the association analysis. A total of 30 fishes with 5 samples from fast and slow growth of each family were utilized. Nineteen EST-derived microsatellite markers were used to genotype 30 DNA samples of the fast and slow growth fishes. Out of 19 loci, 14 loci (i.e., OMO392, OMO051, OMO097, OMO072, OMO327, OMO277, OMO122, OMO193, OMO198, OMO200, OMO335, OMO374, OMO049, and OMO069) were found polymorphic. Another 4 loci (i.e., OMO059, OMO068, OMO315, and OMO337) were observed as monomorphic. Based on the genotype data, there appeared to indicate a strong, significant relationship between allele and growth of the A3 allele of OMO392 locus in the fast growth group. However, no significant genotypes regarding 19 EST-microsatellite were found to be related with growth. This study suggests that the identified allele A3, which has designated the growth hormone related EST-derived microsatellite primer OMO392, can potentially be used to facilitate marker-assisted selection regarding the fast growth of O. niloticus.