Polymorphisms of the melatonin receptor 1A gene that affects the reproductive seasonality and litter size in Small Tail Han sheep

Abstract

Previous researches have shown that MTNR1A plays an essential role in sheep reproduction. However, most researches focused more on the reproductive seasonality of sheep, and few scientists had studied the association of polymorphisms of the MTNR1A gene with ovine litter size and reproductive seasonality. Therefore, we chose MTNR1A gene to detect its novel sequence polymorphisms and population genetics and analyse their association with seasonal reproduction and litter size in ewes. The mRNA expression level in hypothalamus, pituitary and ovary was also detected. In this study, five polymorphisms (g.15118664G > T, g.15118683C > T, g.15118756C > T, g.15118774C > T and g.15118951G > A) were identified in exon 2. Most importantly, the g.15118683C > T and g.15118951G > A were significant difference between year‐round oestrous sheep and seasonal oestrous sheep (p < .01), and g.15118756C > T had a great effect on litter size of Small Tail Han sheep (p < .05). In addition, the mRNA expression level of MTNR1A in the hypothalamus of polytocous Small Tail Han sheep was significantly higher than that in monotocous Small Tail Han sheep (p < .01) and the expression of MTNR1A in the hypothalamus of year‐round oestrous sheep was significantly higher than that in seasonal oestrous sheep (p < .01). Polymorphisms in exon 2 may regulate the reproductive seasonality and litter size of ewes by influencing gene expression to regulate the reproductive seasonality and litter size of ewes. Our studies provided useful guidance in marker‐assisted selection of the litter size in Small Tail Han sheep.

The effect of SNP rs400827589 in exon 2 of the MTNR1B gene on reproductive seasonality and litter size in sheep

“…However, there are few reports about MTNR1B . In our early study on variation of the genome in 89 sheep, we found a significant single nucleotide polymorphism rs400827589 in the re‐sequencing data (Pan et al., 2018), and several other significant SNPs from which have been published in our early reports (He, Zhang, Liu, & Chu, 2019; Zhou et al., 2018). Therefore, in order to better understand the function of this mutation in MTNR1B , we explored the polymorphic distribution using a large population and then investigated the association with litter size and reproductive seasonality in sheep.…”

Analysis of Expression Profiles of mRNA and lncRNA in Oviduct During Estrus Phase of Sheep (Ovis Aries) with Two Fecundity (FecB Gene) Genotypes

“…As the connection between the ovary and the uterus [21], recent researches demonstrated that oviduct is essential in hosts fertilization and preimplantation development of the embryo [22][23][24], however, the in-depth molecular mechanisms have not been elucidated. In the present study, an indigenous Chinese sheep with sheep (Ovis aries) breed with excellent lambing performance (year-round estrous, 2.61 lambs per year on average), STH sheep [25,26] was selected, RNA-Seq was performed on oviduct to investigate the transcriptomic pro les during follicular phase and luteal phase in sheep with two FecB genotypes.…”

Single-nucleotide polymorphisms in &lt;i&gt;FLT3&lt;/i&gt;, &lt;i&gt;NLRP5&lt;/i&gt;, and &lt;i&gt;TGIF1&lt;/i&gt; are associated with litter size in Small-tailed Han sheep

“…Combined with our previous data on 768 sheep from seven breeds, which was collected via whole-genome resequencing, some SNPs were screened out (Zhang et al, 2019(Zhang et al, , 2020He et al, 2019), including rs421947730 and rs160510212 of FLT3; rs429977514, rs408772397, and rs426897754 of NLRP5; and g.37866222C > T and rs1092900782 of TGIF1. Primers to genotype these SNPs were designed by MassAR-RAY® Assay Design (v.3.1).…”