Polymorphism of the melatonin receptor 1A (MNTR1A) gene and association with seasonality of reproductive activity in a local Greek sheep breed.

Ioannis A Giantsis,George P Laliotis,Olympia Stoupa,Melpomeni Avdi

doi:10.1186/s40709-016-0050-y

Ioannis A Giantsis, George P Laliotis + Show 2 more

Open Access

https://doi.org/10.1186/s40709-016-0050-y

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Abstract

BackgroundSheep’s reproductive physiology in temperate latitudes (such as Greece), is characterized by seasonality and is also regulated by photoperiodic exposure. Melatonin is the key hormone involved in this regulation. However, the melatonin secretion and therefore the ewes reproductive activity underlies variation, proposed to be linked with the melatonin receptor subtype 1A (MNTR1A) gene structure. This study was designed to investigate the polymorphism of the MNTR1A gene in a local Greek sheep breed and to determine its potential association with reproductive seasonality.ResultsTwo groups of farmed ewes, each consisted of 30 individuals, were chosen. Males were introduced in both groups in spring (April). The first group consisted of ewes that showed reproductive activity in spring (May), while the second of ewes that showed reproductive activity 3 months later, in summer. The PCR–RFLP methodology was carried out on a 824-bp DNA fragment of the MTNR1A exon 2 using the RsaI restriction endonuclease. The electrophoretic procedure revealed three genotypes, C/C, C/T and T/T. Specifically, 44 animals showed the C/C genotype (28 from the first group and 16 from the second), 14 the C/T genotype (2 from the first and 12 from the second) and 2 animals had the T/T genotype (both from the second group).ConclusionsStatistical analysis indicated a positive correlation between genotype and reproductive seasonality, with C/C genotype playing a crucial role in out-of-season reproduction activity.

Highlights

Sheep’s reproductive physiology in temperate latitudes, is characterized by seasonality and is regulated by photoperiodic exposure
Reproductive activity in sheep living in temperate latitudes, exhibits a seasonal variation that it is regulated by photoperiodic exposure
Reproductive activity in sheep reared in Greece, is characterized by photoperiodism and reproductive seasonality resulting in concentrations of births and milk production in specific periods of the year

Summary

Introduction

Sheep’s reproductive physiology in temperate latitudes (such as Greece), is characterized by seasonality and is regulated by photoperiodic exposure. Reproductive activity in sheep living in temperate latitudes (such as Greece), exhibits a seasonal variation that it is regulated by photoperiodic exposure. This trait, known as reproductive seasonality, results in concentration of births in certain periods of the year. A big variety of commercially important or traditionally made Greek cheeses, such as “feta”, “graviera” and “kefalotyri”, are produced by ovine milk, which, remains in demand by the market throughout the whole year. The finding of less sensitive to reproductive seasonality genotypes, would be a fair alternative in order to rear polyestrus animals that could show reproductive activity regardless of the period of the year, avoiding that way any hormonal treatment

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