A novel 23 bp indel mutation in PRL gene is associated with growth traits in Luxi Blackhead sheep.

Prolactin is a highly versatile pituitary hormone with multiple biological functions. PRL expression is regulated by POU1F1 and the prophet of POU1F1 (PROP1). The aim of this study was to investigate the indel variations in ovine PRL and the directly related (PROP1 and POU1F1) genes, and their associations with growth traits in Luxi Blackhead (LXBH) sheep. A monomorphism in PROP1 and POU1F1 genes, and one novel 23-bp insertion mutation in the PRL gene, were identified in LXBH sheep. The 23 bp insertion mutation within PRL gene was significantly associated with several body measurements (e.g., body weight, body height) in sheep of different ages (p < 0.05). Ram lambs (p = 0.036) of genotype insertion/insertion (II) had significantly higher body weights. Weaners (p = 0.018) of genotypes insertion/insertion (II) and insertion/deletion (ID) also had significantly higher body weights compared with male sheep of deletion/deletion (DD) genotype. Moreover, among ewe lambs, individuals of genotype insertion/insertion (II) had a higher paunch girth compared to those with other genotypes (p = 0.044). These findings indicate that a 23 bp indel variant of the ovine PRL gene is correlated with body measurements in LXBH sheep. The findings have potential utility for sheep breeding programs based on marker-assisted selection.