Polymorphisms in hormone-sensitive lipase and leptin receptor genes and their association with growth traits in Barki lambs.

BACKGROUND AND AIM

Marker-assisted selection has many advantages over conventional selection in animal breeding. The candidate gene approach has been applied to identify genetic markers associated with economically important traits in livestock. This study was established to investigate variation in the hormone-sensitive lipase () and leptin receptor () genes, and their association with growth traits in Barki lambs.

MATERIALS AND METHODS

Records for birth weight (BW), pre-weaning average daily gain (ADG1), weaning weight (WW), post-weaning average daily gain (ADG2), and marketing weight (MW) were obtained from 247 Barki lambs. Polymerase chain reaction-single-stranded conformational polymorphism analyses were used to detect variation in exon 9 of and exon 19 of . General linear models were used to test for associations between the variation in ovine and , and growth traits.

RESULTS

The SSCP banding patterns for showed three variants (, , and ), which contained two nucleotide-sequence differences (c.1865C>T and c.2038T>C). Two SSCP banding patterns ( and ) were observed for and these contained two nucleotide-sequence differences (c.2800G>A and c.2978C>G). The genotype showed no effect on the studied traits. The genotype was proven to have significant effects (p<0.05) on ADG2 and MW. The presence of the variant was associated (p<0.01) with decreased ADG2 and MW.

CONCLUSION

The finding of an association between R gene variation and growth rate after weaning in Barki lambs warrants efforts to improve this trait.