Single nucleotide polymorphisms in the growth hormone gene ofOreochromis niloticusand their association with growth performance

Abstract

Polymorphisms in the growth hormone (GH) gene that is associated with the growth rate of farmed fish have been the target of many breeding programmes. The present study aimed to identify single nucleotide polymorphisms (SNPs) in GH gene regions to evaluate the association of SNP variations with the growth rate of two Nile tilapia: Oreochromis niloticus (Linnaeus, 1758) strains. The targeted regions were amplified, sequenced, aligned and screened for the presence of SNPs; thereafter, performance tests were used to check for the association between SNPs and weight. Allele and genotype frequencies were estimated for each SNP and genotype. Genotype blocks or sets of SNP genotypes and frequencies were also estimated. Association between SNPs and growth rate was statistically evaluated using a univariate linear mixed model that included both fixed and random effects. A total of 10 SNPs were identified, nine in the proximal promoter and one located in the 5′ UTR, forming 10 genotype blocks. In all weight recordings, five genotype blocks were significantly associated with the highest weights. Single nucleotide polymorphisms 6‐10 were also found to be significantly associated with growth (p‐value < .05). Genotypes with higher additive genetic values for weight were identified in the Chitralada strain, suggesting a possible impact of these additive effects of the GH SNP genotype on the growth rate of Nile tilapia. These findings may be used as part of marker‐assisted selection in tilapia breeding programmes.

Identification and analysis of a novel microsatellite marker within the growth hormone gene promoter of Colossoma macropomum (Characiformes: Characidae) detected by TAIL‐PCR

“…Jaser et al. (2017) identified SNPs in the promoter region of the GH gene of a hatchery population of Nile tilapia and associated the markers with individual growth rate. Li et al.…”

Growth hormone gene polymorphism associated with grow-out performance of Oreochromis niloticus strains

“…The second study carried out a more extensive search for SNPs in the promoter and intron-I of two strains of Nile tilapia. As a result, a significant association was found between the promoter's SNPs and growth rate using a univariate linear mixed model (Jaser et al, 2017).…”

“…Data were obtained from two genetically distinct strains of Oreochromis niloticus, Red-Stirling and Chitralada, and their crossbreeds. Seven genetic groups were obtained by backcross breeding (Lago et al, 2017), as shown in Table 1. The progenies from the seven genetic groups were obtained in mating hapas (8 × 6 × 2 m 3 ) using one dam with two sires after two-week intervals to synchronize spawning (Tsadik, 2014).…”

“…All grow-out procedures were described by Lago et al (2017), including water quality parameters and feeding regime. The following measures were taken to estimate the performance: body weight (BWe), standard length (SL), body height (BH), body width (BWi), head height (HH), head length (HL).…”

Species composition in the Molobicus hybrid tilapia strain

“…Enhanced growth is a known attribute of the O. niloticus species and the main selection drive within the GIFT selection programme (Ponzoni et al, 2011), so perhaps a proportion of the O. niloticus SNP panel could reflect a growth advantage. Efforts on ongoing to unravel the genetic basis for growth selection with polymorphisms in the growth hormone gene implicated in O. niloticus (Jaser et al, 2017) and multiple linkage groups (LGs) associated with growth in saline tolerant hybrid tilapia derived from O. mossambicus and Asian red tilapia (Lin et al, 2016).…”