Ibrahim, A. H. M.Zhou, HuitongHickford, Jonathan G. H.2020-04-2220150302-4520https://hdl.handle.net/10182/11763The aim of this study was to further investigate the variation in growth and differentiation factor 8 (GDF8) gene and its association with growth and carcass characteristics of New Zealand Romney sheep. Polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis was used to detect the polymorphisms in intron 1 of ovine GDF8 gene in 447 New Zealand Romney lambs produced from 17 sire-lines. PCR-SSCP analysis identified a total of six SSCP genotypes, AA (0.111), AB (0.367), AC (0.100), BB (0.288), BC (0.128) and CC (0.006) representing three alleles A, B and C with frequency of 0.34, 0.54 and 0.12, respectively. General linear mixed effect models revealed a significant effect (P< 0.05) for GDF8 genotype on loin yield and percentage loin yield. The presence of allele B was significantly associated with increased loin yield (P< 0.05) and percentage loin yield (P< 0.01). Effects of number of allele copies present on the studied traits were assessed. Loin yield and percentage loin yield were significantly (P< 0.05) affected by number of allele B copies. Having one copy of allele B was associated with increased loin yield, total yield and percentage loin yield; however, having two copies of allele B was associated with decreased loin yield and total yield. Our present results suggest that GDF8 polymorphism is mainly associated with loin yield and percentage loin yield and has no effect on birth weight, weaning weight and growth rate in New Zealand Romney sheep.39-46 (7)en© ESAPgrowthcarcassGDF8PCR-SSCPRomney sheepJournal Article