Single-nucleotide polymorphisms in FLT3, NLRP5, and TGIF1 are associated with litter size in Small-tailed Han sheep.

Si Chen,Lin Tao,Mingxing Chu,Xiaoyun He,Ran Di,Xiangyu Wang

doi:10.5194/aab-64-475-2021

Abstract

Previous studies have indicated that FLT3, NLRP5, and TGIF1 play a pivotal role in sheep fecundity. Nevertheless, little is known about the association of the polymorphisms of these genes with litter size (LS). In this study, the selected single-nucleotide polymorphisms (SNPs) were genotyped using a Sequenom MassARRAY® platform, and the distribution of different genotypes of the SNPs in the seven sheep breeds (Small-tailed Han, Hu, Cele Black, Suffolk, Tan, Prairie Tibetan, and Sunite sheep) were analyzed. The reliability of the estimated allele frequency for all seven SNPs was at least 0.9545. Given the association of the TGIF1 g.37866222C T polymorphism with LS in Small-tailed Han sheep (), fecundity differences might be caused by the change in amino acid from proline (Pro) to serine (Ser), which has an impact on secondary, tertiary protein structures with concomitant TGIF1 functionality changes. The FLT3 rs421947730 locus has a great effect on the LS (), indicating that the locus of FLT3 in synergy with KILTG is likely to facilitate ovarian follicle maturation and ovulation. Moreover, NLRP5 rs426897754 is associated with the LS of the second and third parities (). We speculate that a synonymous variant of NLRP5 may be involved in folliculogenesis accompanied by BMP15, FSHR, BMPR1B, AMH, and GDF9, resulting in the different fecundity of Small-tailed Han sheep. Our studies provide valuable genetic markers for sheep breeding.

Highlights

Many physiological parameters involved in animal reproduction have an important role in the productivity of farm animals
Seven potential single-nucleotide polymorphisms (SNPs) were located in the exon region, including six synonymous variants and one missense variant
Our study revealed that the TGIF1 missense variant g.37866222C > T showed a significant increase in litter size (LS) at the second and third parity and that mutant-type ewes (CT) displayed the maximum LS (p < 0.05)

Summary

Introduction

Many physiological parameters involved in animal reproduction have an important role in the productivity of farm animals. It has been established that melatonin administration can be used to modify seasonal breeding patterns in goats and sheep (Deveson et al, 1992, Mura et al, 2010) or to decrease milk yield by altering prolactin concentrations in lactating ewes (Molik et al, 2013). Manipulation of photoperiod and melatonin treatment are widely used for the control of reproduction in goats and sheep (Carcangiu et al, 2015, Giannetto et al, 2020, 2021). The measure of sheep fertility is the litter size (LS) of ewes; increasing the LS plays a pivotal role in developing the sheep industry. That is, combining traditional selection with modern molecular breeding technology greatly boosts the efficiency of sheep breed selection, further improving reproductive performance (Notter, 2012)

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Discussion

Conclusion