Genetic variability of bovine GHR, IGF-1 and IGFBP-3 genes in Indian cattle and buffalo

Kp Ramesha,Ma Kataktalware,Akhila Rao,S Jeyakumar,M Basavaraju,Gr Geetha

doi:10.4314/sajas.v45i5.5

Abstract

The identification of genetic polymorphisms in the genes that play a crucial role in regulatiing growth and development of livestock enables us to evaluate the biological similarities and to acquire a better perspective of quantitative traits. The present study was undertaken to characterize genetic variability in the bovine growth hormone receptor (GHR), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) genes among Bos indicus (Malnad Gidda, Khillar), Bos taurus (Holstein Friesian, Jersey) cattle and Asian water buffalo Bubalus bubalis (Murrah, Surti) using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. These polymorphisms were confirmed by direct sequencing. The comparative gene sequence analysis in cattle and buffalo breeds revealed 18 single nucleotide polymorphisms (SNPs) across different loci. Eight SNPs were detected in the bovine growth hormone receptor (GHR) gene, of which four were found in the promoter region and four in the exon 4 region. In the IGF-1 gene, two SNPs were observed in the 5ˈUTR, three SNPs in the intron 3 region and two SNPs in the coding region of exon 4. Three SNPs were detected in the exon 2 region of the bovine IGFBP-3 gene. The frequency of rare alleles observed in the present study ranged from 0.04 to 0.16. The present results revealed high levels of genetic variability in the GHR, IGF-1 and IGFBP-3 genes in cattle and buffalo reared in India. Keywords: PCR-SSCP, genetic polymorphism, cattle, buffalo

Highlights

In dairy animals, growth and reproduction are two key traits to be considered for genetic improvement of production efficiency
The present study aimed to identify and characterize polymorphisms in the promoter and coding regions of the growth hormone receptor (GHR), Insulin-like growth factors (IGFs)-1gene and a section of the insulin-like growth factor binding protein 3 (IGFBP-3) genes among different breeds of cattle (Malnad Gidda, Khillar, Holstein Friesian and Jersey) and buffalo (Murrah and Surti) using PCR-SSCP technique
Two types of SSCP band patterns (Pattern I and Pattern II) were observed in all the cattle and buffalo breeds screened for the promoter region of growth hormone receptor gene (GHR-P, Figure 1) and the 5ˈ UTR region of IGF1-A

Summary

Introduction

Growth and reproduction are two key traits to be considered for genetic improvement of production efficiency. Genetic markers for quantitative trait loci that are linked to the causal genes could be used to select animals for breeding programmes. Identification and use of markers for milk quality and production traits, disease resistance and thermo-tolerance would ensure better health and productivity (Singh et al, 2014). Molecular techniques such as polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) are effective tools in the animal breeding domain for providing breeders an opportunity to identify and select superior animals based on genotypes associated with particular traits of interest (Bastos et al, 2001). Earlier research on GHR, IGF-1 and IGFBP-3 in cattle, goats and chickens showed genetic polymorphisms and their association with production traits (Pereira et al, 2005; Liu et al, 2010)

Methods

Results

Conclusion