Polymorphisms of the PRLR Gene and Their Association with Milk Production Traits in Egyptian Buffaloes

Abstract

Prolactin (PRL) and its receptor (PRLR) were considered as potential genetic markers for milk production and quality traits in cattle. However, little information is available regarding PRLR genetic diversity and association studies with milk traits in Egyptian water buffaloes. Therefore, the present study was conducted to search for mutations in PRLR and determine their associations with milk performance in these animals. Exon3 (E3) and E10 of PRLR were screened for polymorphisms using single strand conformation polymorphism (SSCP) and sequencing in 400 buffaloes. The associations between haplotypes and milk production (fat%, protein%, lactose%, and solid%) traits as well as mRNA and protein levels of PRL and PRLR were studied. Two single nucleotide polymorphisms (SNPs) in E10 were detected: g.11685G>A (p.Ala494Thr) and g.11773T>C (p.Val523Aal). The G and T alleles were wild (ancestral) alleles, while the A and C alleles were mutant alleles. These SNPs resulted in four haplotypes; AC, AT, GC, and GT. Buffaloes with wild GT haplotypes showed significantly higher milk yield, fat% and protein%, mRNA and protein levels of PRL and PRLR in milk somatic cells than other animals. Animals carrying mutant AC haplotype had inferior milk traits and lowest levels of associated mRNAs and proteins. With these results, we could conclude that the selection of buffaloes with wild GT haplotypes for g.11685G>A and g.11773T>C SNPs of the PRLR gene might improve the milk production traits of Egyptian water buffaloes.

A transcriptomic analysis of skeletal muscle tissues reveals promising candidate genes and pathways accountable for different daily weight gain in Hanwoo cattle

“…According to Chu et al, the PRLR gene closely related to prolactin signaling pathway is a candidate gene for prolificacy of small tail trait in han sheep 33 . In Egyptian Buffaloes, the PRLR has shown promise as a genetic marker for evaluating milk production and quality traits 34 . Additionally, another gene associated with the prolactin signaling pathway, MAPK13 (mitogen-activated protein (MAP) kinase family), exhibited downregulation.…”

ABCD4 is associated with mammary gland development in mammals

“…From an animal breeding perspective, our prior study identified the most significant locus associated with teat number in the ABCD4 region [ 8 ], a finding supported by recent research [ 25 ]. Meanwhile, polymorphisms of the PRLR gene have been associated with reproductive traits and milk production traits in pigs, goats, sheep and dairy cattle [ 37 – 40 ]. Specifically, animals with different PRLR genotypes show significant differences in the number of functional teats, age at first estrus, litter size, and litter average [ 22 , 41 ].…”

A transcriptomic analysis of skeletal muscle tissues reveals promising candidate genes and pathways accountable for different daily weight gain in Hanwoo Cattle

“…According to Chu et al, the prolactin receptor (PRLR) is a candidate gene for proli cacy of small tail han sheep 36 . In Egyptian Buffaloes, the Prolactin receptor (PRLR) has shown promise as a genetic marker for evaluating milk production and quality traits 37 . The current experiment revealed a signi cant upregulation of the PRLR gene by a log2FC of 3.05.…”