Detection of mRNA Expression and Copy Number Variations Within the Goat Fec B Gene Associated With Litter Size

Abstract

The Booroola fecundity (Fec ^B ) gene, as the first major fecundity gene identified in Booroola sheep, has attracted careful attention. So far, previous research have uncovered the Fec^B mutation (Q249R) as the main mutation by virtue of which sheep exhibits multiple lambing phenomena. This mutation is now being intensively studied and widely used. However, such effect of the Fec^B mutation has not been applied to goats, and similar types of the Fec ^B gene in goats still need to be studied. Thus, the current study attempted to verify potential mutations in the goat Fec ^B gene as well as investigate their functions related to fecundity. First, Fec ^B expression was investigated in six different goat tissues, and we found that Fec ^B expression was highest in the mammary gland, followed by the ovary. Next, the influence of the Fec ^B gene was analyzed from a new perspective, where five potential copy number variations (CNVs) (CNV1-5) within the Fec ^B gene were identified for the first time, and then their effects on litter size were measured. Our results point out that CNV3 (P = 3.44E-4) and CNV5 (P = 0.034) could significantly influence the litter size of goats. Identically, the combination genotype of CNV3 and CNV5 which consisted of their dominant genotypes was also significantly associated with goat litter size (P = 7.80E-5). Hence, CNV3 and CNV5 could serve as potential DNA molecular markers applied to DNA editing and DNA microarray. Additionally, the abovementioned study has laid a theoretical foundation for the detection of potential fertility-related quantitative trait loci within the goat Fec ^B gene.

Keywords: CNV; FecB gene; goat; litter size; mRNA expression.

Figure 1

Gene structure of the goat Fec^B gene.

Figure 2

The mRNA expression profile of goat Fec^B gene, using the corpus luteum and large follicle as references (selecting three individuals for each tissue with three parallel repeats). *P < 0.05; **P < 0.01.

Figure 3

Association analysis between litter size and copy number variations (CNVs) in Shaanbei white cashmere goats. (A) Association between CNV3 and litter size. (B) Association between CNV5 and litter size.

Figure 4

Least squares mean and standard error for litter size of the different combination genotypes of CNV3 and CNV5 within the Fec^B gene in Shaanbei white cashmere goats. Combination genotypes with a sample size of less than five were not calculated.