Single nucleotide polymorphism identification and characterization of GnRHR gene in Bos taurus and Bos indicus cattle

Authors: RAMESHA KEREKOPPA, MARAPPA BASAVARAJU, AKHILA RAO, GUJJAR RAMACHANDRA GEETHA, Kataktalware Mukund, JEYAKUMAR SAKTHIVEL

Abstract: The hypothalamic gonadotropin-releasing hormone receptor (GnRHR) plays an essential physiological role in reproductive function. In this investigation, we studied genetic variation in the entire coding region of GnRHR gene using PCR-SSCP technique in 250 Bos taurus (Holstein Friesian, Jersey) and Bos indicus (Malnad Gidda, Deoni) bulls. The genetic variants in GnRHR gene were determined by PCR-SSCP technique by using 5 sets of primers. SSCP analysis of fragment 1, comprising exon 1, and fragment 3, comprising exon 2, revealed 2 SSCP patterns in all breeds under study, while fragment 2 of exon 1 and fragment 4, comprising exon 3, revealed 3 patterns in Malnad Gidda; Holstein Friesian and Deoni breeds showed 2 SSCP patterns. In Jersey bulls, fragment 4 showed 3 patterns. The fragment 5 comprising exon 3 was monomorphic in all 4 breeds under study. SNPs were confirmed by direct sequencing. The sequence analysis revealed 7 transitions (T940C, T1021C, T1090C, T1174C, T13940C, T18023C, and G17887A), 3 transversions (G13817C, G17926C, and G17926C), 2 deletions (854DA and 17684DT), and 2 insertions (1009IA and 180100IC) in GnRHR gene. The study revealed high genetic variation in GnRHR gene in cattle.

Keywords: GnRHR, PCR-SSCP, single nucleotide polymorphism, cattle

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