Genetic Polymorphisms in New Zealand Sheep Breeds - Agriculture and Soil Science

Animal production is a booming industry with the improvement of economically desirable traits as its primary concern. Marker-assisted selection utilizes genetic variations within candidate genes that influence production traits as a means of guiding animal breeding and improving the traits of interest. Growth hormone (GH) plays a crucial role in pre-natal muscular and bone growth and development. GH brings about various physiological functions either directly by binding its receptor or indirectly by stimulating the release of insulin growth factor 1 (IGF1). Insulin growth factor 1 receptor (IGF1R) mediates its function on metabolism, homeostasis and  development  upon  the  binding  of  IGF1.  The  POU-domain  class  1  transcription  factor  1  (POU1F1)  regulates  the  pre-natal  development  of  cells  of  the  anterior  pituitary,  including  somatotrophs  that  produce  GH.  Reports  have  demonstrated  associations  between polymorphisms in these genes and animal production traits. This novel study examined the polymorphisms in the coding regions of candidate genes, GH2Z, IGF1R and POU1F1, in New Zealand (NZ) sheep. The sheep breeds investigated were NZ Romney and Merino, two commercially sought-after breeds. The results revealed two variants, AA and AB, for the exon 3 of POU1F1. The AA  and  AB  genotypes  had  frequencies  of  78%  and  22%  for  Romney  sheep,  and  64%  and  36%  for  Merino  sheep  respectively.  All  frequencies were in accordance with the Hardy-Weinberg Equilibrium (P > 0.05). The exon 2 of GH2Z revealed multiple variations while no variation was detected for the exon 15 of IGF1R.

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