STUDIES ON GROWTH HORMONE GENE POLYMORPHISM IN NELLORE SHEEP THROUGH PCR-SSCP
Dr. S.T.VIROJI RAO
2018-12-14
M.V.Sc.
A total of about 50 unrelated animals of Nellore brown sheep belonging to different flocks including, Livestock Research Station (LRS), Mamnoor, Instructional Livestock Farm Complex (ILFC), Rajendranagar of P.V.Narsimha Rao Telangana Veterinary University and farmers flocks from Shamshabad region of Ranga Reddy district were screened to explore the polymorphism of different regions of growth hormone (GH) gene using PCR-SSCP technique. The PCR-SSCP of 5ꞌ regulatory region (210 bp) yielded three SSCP patterns 11, 12 and 22 corresponding to two allelic variants 1 and 2. The allelic frequency of 1 and 2 were 0.45 and 0.55, genotypic frequencies were 0.24, 0.42 and 0.34 in 11, 12, and 22, respectively. The exon-4 (191 bp) yielded two genotypic patterns 11 and 12 corresponding to two allelic variants 1 and 2. The allelic frequency of 1 and 2 were 0.80 and 0.20, genotypic frequencies were 0.60 and 0.40 in 11 and 12, respectively. The PCR-SSCP yielded two conformational patterns 11 and 12 in exon-5 (480 bp) indicating polymorphism in Nellore sheep with two alleles 1 and 2. The allelic frequency of 1 and 2 were 0.85 and 0.15, respectively, genotype frequencies of 11 and 12 were 0.70 and 0.30, respectively. The PCR-SSCP of 3ꞌ UTR (320 bp) yielded two different conformational patterns 12 and 13 corresponding to three allelic variants 1, 2 and 3. The allelic frequencies of 1, 2 and 3 were 0.50, 0.31 and 0.19, respectively and genotype frequencies were 0.62, 0.38 for 12 and 13, respectively. The least square means obtained for body weight, body length, height at withers and heart girth were 25.93 ± 0.20 kg, 71.46 ± 0.43 cm, 74.17 ± 0.17 cm, 75.70 ± 0.53 cm, respectively at 12 months of age in Nellore sheep. PCR-SSCP patterns of different portions of GH gene were correlated with body weights and morphometric traits at 12 months of age. It was observed that the overall mean BW, BL, HAW and HG values were 26.03 ± 0.42 kg, 72.00 ± 0.77 cm, 74.54 ± 0.30 cm and 75.97 ± 1.16 cm in animals with pattern 11, while with pattern 12 the values were 25.88 ± 0.35 kg, 70.81 ±0.71 cm, 74.21 ± 0.29 cm and 75.76 ± 0.81 cm and with xvii pattern 22 were 25.91 ± 0.32 kg, 71.18 ± 0.75 cm, 73.87 ± 0.29 cm and 75.44 ± 0.94 cm, respectively in 5ꞌ regulatory region (210 bp) of GH gene. The present findings showed slight variation in body weights and morphometric traits. In exon-4 (191 bp), mean BW, BL, HAW and HG in pattern 11 were 26.08 ± 0.25 kg, 71.93 ± 0.55 cm, 74.35 ± 0.25 cm and 75.96 ± 0.68 cm and in pattern 12 were 25.71 ± 0.35 kg, 70.75 ± 0.67 cm, 73.91 ± 0.21 cm and 75.32 ± 0.88 cm, respectively. The present study clearly shows slight variation in body weights and morphometric traits. The overall mean BW, BL, HAW and HG were 26.11 ± 0.27 kg, 71.68 ± 0.53 cm, 74.24 ± 0.21 cm, 75.52 ± 0.67 cm in animals with pattern 11 of SSCP portion of exon-5 (480 bp),whereas for pattern 12, the corresponding values were 25.50 ± 0.25 kg, 70.94 ± 0.74 cm, 74.00 ± 0.30 cm, 76.13 ± 0.89 cm, respectively. The present study indicated slight variation in BW and other morphometric traits between patterns obtained. BW, BL, HAW and HG were 25.75 ± 0.23 kg, 71.16 ± 0.61 cm, 74.24 ± 0.23 cm, 75.10 ± 0.63 cm, for those showing pattern 12 of 3' UTR (320 bp) region, and in those with pattern 13 the values for BW, BL, HAW and HG were 26.22 ± 0.38 kg, 71.94 ± 0.53 cm, 74.06 ± 0.27 cm, 76.69 ± 0.93 cm, respectively. The animals with pattern 13 had slightly higher values for BW and HG. Identification of different SSCP patterns confirmed the polymorphism within 5ꞌ regulatory region, exon-4, exon-5 and 3ꞌUTR of GH gene in Nellore sheep. This investigation indicated that SSCP analysis is a valuable tool for the identification of genetic polymorphism. The SSCP patterns (various genotypes) obtained in the present study for various segments of growth hormone gene and their relationship with body weights and other morphometric traits at 12 months age did not show significant differences among genotypes. To establish the real connection between genotypes and various traits if any requires large population of wide genetic base with accurate data.
en
91
PVNR TVU
Animal Genetics and Breeding
AGB
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2018 D605 Dr.B.Rajith Reddy AGB PG.pdf