Evaluation of candidate genes related to litter traits in Indian pig breeds

Abstract

Improvement in litter traits is the key to profitable pig farming that directly enhances the economic standing of the farmers in developing countries. The present study aimed to explore oestrogen receptor (ESR), epidermal growth factor (EGF), follicle‐stimulating hormone beta subunit (FSHβ), prolactin receptor (PRLR) and retinol‐binding protein 4 (RBP4) genes as possible candidate genetic markers for litter traits in indigenous pigs of India. The breeds included in the study were Ghungroo, Mali, Niang Megha and Tenyi Vo, and the reproductive traits considered were litter size at birth (LSB), number born alive (NBA), litter weight at birth (LWB), litter size at weaning (LSW) and litter weight at weaning (LWW) at their first parity. PCR‐RFLP and primer‐based mutation detection methods were used to identify polymorphism, and associations between the genotypes and the traits were analysed using a general linear model. The Ghungroo pigs recorded the best litter performances among the breeds (p < .05, LWB p < .01). Different alleles and genotypes of the genes under study were detected. Short interspersed nuclear element (SINE) −/− genotype of FSHβ revealed significantly higher litter traits (p < .05, LSB p < .01). The LWW was also found to be significantly influenced by ESR BB and AB, EGF AB and BB, and PRLR CC genotypes (p < .05). Although we did not find statistically significant and consistently superior litter traits with respect to different genotypes of other studied genes than genotype SINE −/− of the FSHβ, PRLR CC genotype demonstrated superior performances for all the litter traits. Our study revealed the FSHβ as a potential candidate genetic marker for litter traits in indigenous pig breeds of India.

Genome-Wide Association Studies and Runs of Homozygosity to Identify Reproduction-Related Genes in Yorkshire Pig Population

“…The results of ROH detection show that the number of five kinds of ROH segments were: 141,334 (0-6 Mb), 8573 (6)(7)(8)(9)(10)(11)(12), 3853 (12-24 MB), 1249 , and 292 (>48 Mb), respectively. The number and proportion of ROH on each chromosome are shown in Supplementary Figure S1.…”

“…Litter size directly reflects the productivity of pigs per sow per year [5]. Many researchers have dedicated their efforts to identifying SNPs and candidate genes that are associated with litter size [6][7][8], but there is still a long way to go to improve pig reproduction.…”

Effect of SNPs on Litter Size in Swine

“…After screening, the genes on which there were more than seven studies were ESR, PRLR, RBP4, and FSH β. A total of 94 datasets from 37 papers were used for LS traditional meta-analysis [1,12,[16][17][18][19][20][21][22], as shown in Figure 1A. Figure 1B shows that ESR, PRLR, RBP4, and FSH β SNPs were positively correlated with the absolute value of LS.…”

“…Therefore, many studies have focused on improving LS. These methods include, but are not limited to, the PCR-RFLP/SSCP verification of candidate genes [1], genome-wide association studies (GWASs) [2], QTL [3], epigenetics [4], mitochondrial DNA [5], micro RNA (miRNA) [6,7], long noncoding RNAs (lncRNAs) [8], and circular RNAs (circRNAs) [9]. The studies mentioned above were conducted based on the genetic perspective.…”

Genome-Wide Association Studies, Runs of Homozygosity Analysis, and Copy Number Variation Detection to Identify Reproduction-Related Genes in Bama Xiang Pigs

“…Teat number is a proxy for lactation ability and, thus, is related to piglet mortality rates ( 22 ). Numerous researchers have focused on identifying SNPs, quantitative trait loci (QTLs), and candidate genes associated with litter size and teat number ( 23 – 25 ). However, the studies of quantitative traits based on CNVs have rarely been completed, especially on litter size and teat number.…”