Genotyping of Growth Hormone Gene in Egyptian Small Ruminant Breeds

Abstract

A B S T R A C T Small ruminants are considered as one of the major sources of meat and milk production in Egypt. Identification of the genes underlying livestock production traits leads to more efficient breeding programs and it is a promising way to improve production traits of farm animals. Growth hormone is a polypeptide hormone which is the major regulator of the metabolic procedures of growth and development and it is encoded by GH gene. In this study, we aimed to detect the genetic polymorphism of GH gene in major Egyptian sheep and goat breeds using PCR-RFLP and identify the single nucleotide polymorphism between different genotypes detected in these breeds. The primers used in this study flanked a 422 bp fragment from exons 2 and 3 of GH gene in sheep and goat. These PCR amplified fragments were digested with HaeIII endonuclease and the results showed the presence of two genotypes; GG and AG with the absence of AA genotype in 149 tested animals for this gene. The total frequencies were 43.56 and 56.44% for GG and AG genotypes, respectively in 101 tested sheep animals whereas in goat animals, the total frequencies were 12.5 and 87.5% for GG and AG genotypes, respectively in 48 tested goat animals. The sequence analysis of purified PCR products representing these two detected genotypes declared the presence of a SNP (G6A) at position 55 in the amplified fragment which is responsible for the destruction of the restriction site GG^CC and consequently the presence of two different alleles G and A which were named in this work according to the detected SNP. The nucleotide sequences of sheep GH alleles G and A as well as goat GH alleles G and A were submitted to nucleotide sequences database NCBI/Bankit/GenBank and have accession numbers: KP120857, KP120858, KP120859 and KP120860, respectively. In conclusion, production improvements can be achieved by using new genetic technology for better selection of heritable traits through marker-assisted selection. Due to the reported association between genotype possess A/G nucleotide with different growth trait parameters, we recommend to increase this heterozygous genotype in native small ruminant breeds through the selection of animals have AG genotype of GH gene and enter them in breeding programs of Egyptian small ruminants as a way to increase their production traits.

Sequencing and Polymorphism detection in growth hormone gene in Najdi Sheep and their association with milk production

“…Two alleles A and G were detected in Egyptian sheep with two genotypes GG and AA and absence of GA. The frequencies of GG and AG genotypes were 35.56 and 64.44% in sheep Barki animals (45 animals), 19.23 and 80.77% in sheep Rahmani animals (26 animals) and 76.67 and 23.33% in sheep Ossimi animals (30 animals), respectively with the total frequencies of 43.56 and 56.44% for GG and AG genotypes, respectively in 101 tested sheep animals for this gene (Othman et al, 2015).…”

“…Recently, researchers interested in studding the polymorphisms at genes that encoding the livestock economic traits, and use these polymorphisms as a genetic selection markers of individuals with superior traits (Othman et al, 2015). Growth hormone gene, with its functional and positional potential, has been widely used for marker in several livestock species, including the cattle (Katoh et al, 2008), sheep (Marques et al, 2006), goat (Boutinaud et al, 2003) and Arabian camels (Afifi et al, 2014).…”

Polymorphism of growth hormone gene in three goat breeds in Egypt

“…The findings of GH1 gene are in consonance with those reported by Singh et al (2015) who showed that both of Sirohi and Barbari goat breeds were polymorphic at the GH1 locus treated with HaeIII. Likewise, Othman et al (2015) detected a SNP (G → A) at position 55 of GH1 locus (422 bp) in the Egyptian Baladi, Barki, and Zaraibi goat breeds using HaeIII/PCR-RFLP and gene sequencing. Moreover, these results are in agreement with those obtained in Savanna and Kalahari goats by Amie Marini et al (2012).…”

Cloning, nucleotide sequencing, and bioinformatics analyses of growth hormone mRNA of Assaf sheep and Boer goats reared in Egypt

“…The GG and AG genotype frequencies were 35.56 and 64.44% in Barki sheep, 19.23 and 80.77% in Rahmani sheep, and 76.67 and 23.33% in Ossimi sheep, respectively. In goats, the GG and AG genotype frequencies were 0 and 100% for Baladi, 13.33 and 86.67% for Barki, and 23.53 and 76.47% for Zaraibi, respectively [32]. In the present study, the multiple alignments showed that SNP of C/T was observed in both sheep and goat; TCc 248 (Ser 80 ) in Ossimi sheep and TCc 254 (Ser 81 ) in China sheep vs. TCC 251 (Ser 81 ) in all GenBank sheep database, while TCc 246 and TCc 168 for Ser 81 in Indian Tibetan, Lazhi, and Beetal goats vs. TCT 263 for Ser 81 in for all GenBank goat database.…”