Aromatase gene and its effects on growth, reproductive and maternal ability traits in a multibreed sheep population from Brazil

Abstract

We determined the polymorphism C242T of the aromatase gene (Cyp19) and its allelic frequency, as well as the effect of the variants on productive and reproductive traits in 71 purebred Santa Inês sheep, 13 purebred Brazilian Somali sheep, nine purebred Poll Dorset sheep, and 18 crossbred 1/2 Dorper sheep. The animals were genotyped using the PCR-RFLP technique. The influence of the animal's genotype on its performance or on the performance of its lambs was analyzed by the least square method. Another factor assessed was the importance of the animal's genotype in analysis models for quantitative breeding value estimates, and whether there were differences among the averages of breeding values of animals with different genotypes for this gene. In the sample studied, no AA individuals were observed; the AB and BB frequencies were 0.64 and 0.36, respectively. All Brazilian Somali sheep were of genotype BB. All 1/2 Dorper BB animals presented a lower age at first lambing, and the Santa Inês BB ewes presented a lower lambing interval. In these same genetic groups, AB ewes presented higher litter weight at weaning. This is evidence that BB ewes have a better reproductive performance phenotype, whereas AB ewes present a better maternal ability phenotype. However, in general, animals with genotype AB presented better average breeding values than those with genotype BB.

Polymorphism C242T in the Cyp19 gene in meat sheep

“…A greater frequency of allele T was observed in the Dorper, White Dorper and Santa Inês breed groups, corroborating results found by Lôbo et al (2009) in populations composed of ½ Dorper (n=18), Santa Inês (n=71) and Somalis Brasileira (n=13) animals. For the Texel breed group, however, allele C was observed at the highest frequency, disagreeing with the reports of Lôbo (2008), who evaluated the frequency of this polymorphism for ½ Texel sheep and observed a greater frequency for allele T (0.670).…”

“…Vanselow et al (1999) also found allele C in evaluated European sheep, but there are no literature data on genotypic frequency for the CC genotype in sheep. This genotype was not found by Lôbo et al (2009) in several genetic groups evaluated.…”

“…This transition is seemingly related to a greater live weight at slaughter (Tanamati et al, 2013a) and larger loin-eye area (Tanamati et al, 2013b). In addition, this polymorphism seems to cause differences in other performance traits in sheep, influencing reproductive aspects and maternal ability, and is apparently related to different breed groups (Lôbo et al, 2009).…”

Intramuscular fat and fatty acid profile of muscle of lambs finished in irrigated pasture

“…These aspects are controlled by many physiological aspects such the hormones biosynthesis. Lobo et al (2009) determined the polymorphism C242T of the aromatase gene (Cyp19) in some of the breeds of this study that can help explain the differences in the growth and maturing rate of them. Lobo et al (2012) also reported that transcripts involved in skeletal muscle development (MyoD1 and IGFBP4), lipogenesis and adipogenesis (C/ EBPd, PPARg and PGDS) were differentially expressed in some comparisons between the genetic groups studied here.…”

Distribution of Different Alleles of Aromatase Cytochrome P450 (CYP19) and Melatonin Receptor 1A (MTRN1A)Genes among Native Turkish Sheep Breeds

“…As P2 is mainly active in ovarian granulosa cells [21] mutations occurred in these mentioned regions may be significant for obtaining valuable knowledge on reproductive traits. In a previous study some important relationships were determined between the C242T transition and some reproductive traits as litter weight, lambing interval, lambing age, reproductive performance, and maternal ability in Brazilian sheep breeds [22] .…”