GH Gene Polymorphism Research Articles

Effect of GH gene polymorphism on growth traits in goats of Meghalaya’s subtropical hilly region

Effect of GH gene polymorphism on growth traits in goats of Meghalaya’s subtropical hilly region

GH, SEMA3E and TLX gene polymorphism and its association with egg quality traits of quail

This study attempted to determine the relationship between the GH, Sema3E, and TLX genes and egg quality traits using the PCR-RFLP technique in Japanese quail. Three genotypes and two alleles were obtained by cutting the GH gene with the MspI enzyme, the Sema3E gene with the HaeIII enzyme, and the TLX gene with the PstI enzyme. The allele frequency and the frequency of heterozygous genotypes were higher for all genes. There was no statistically significant relationship between egg quality traits and genotypes. However, it was found that the eggs of the animals with the A allele for the GH gene had a higher shape index. Similarly, eggs from animals with the A allele for the Sema3E gene were found to be heavier. In light of previous studies and these results, it is believed that these genes can be used as selection markers for egg quality traits.

Identification of the association of the GH, IGF-I and Pit-I gene polymorphism with growth traits in Saanen, Alpine and Boer goat breed

This study aims to determine an effect between GH, IGF-I, and Pit-I gene polymorphisms and growth traits such as body weight, heart girth, body length, height at wither, and chest width in Saanen, Alpine, and Boer goat breeds. The polymorphism was identified using the PCR-RFLP technique. GH/HaeIII gene polymorphism results identified two alleles (A and B) and two genotypes (AB and BB). A and B allele frequencies for Saanen, Alpine, and Boer goat breeds were found to be 0.438 and 0.562, 0.444 and 0.556, and 0.197 and 0.803, respectively. AB and BB genotype frequencies were found to be 0.876 and 0.124, 0.889 and 0.111, and 0.394 and 0.606, respectively. IGF-I/HaeIII gene polymorphism results identified two alleles (A and B) and three genotypes (AB, BB, and AA). A and B allele frequencies for the Saanen, Alpine, and Boer breeds were found to be 0.191 and 0.809, 0.173 and 0.827, and 0.182 and 0.818, respectively. The AB, BB, and AA genotype frequencies were found to be 0.315, 0.652, and 0.033 for Saanen, 0.247, 0.704, and 0.049 for Alpine, and 0.242, 0.697, and 0.061 for Boer, respectively. Regarding Pit-I/PstI gene polymorphism, T and C allele frequencies were determined as 0.921 and 0.079, 0.988 and 0.012, and 0.985 and 0.015 for Saanen, Alpine, and Boer breeds, respectively. TT and TC genotype frequencies were found to be 0.843 and 0.157, 0.975 and 0.025, and 0.970 and 0.030 in Saanen, Alpine, and Boer goats, respectively. An association was found between GH polymorphism and chest width in Saanen and Alpine goats and between body weight and heart girth in Boer goats. Additionally, an association was identified between IGF-I polymorphism and body weight in Alpine and chest width in Boer. There was also an association between Pit-I polymorphism and body weight in Alpine goats.

Associations of CAST, GH gene polymorphism in young sheep with a blood type of ? Charolais + ? Kalmyk kurdyuchnaya with measurements of body articles and indices of physique

To increase the production of meat productivity, it is necessary to improve the genetic resources of sheep. The purpose of this work was to establish the allelic spectrum of the calpastatin (CAST) and somatotropin (GH) genes, and their associations with meat productivity in young animals of mixed stock with a bloodline of ? Charolais + ? Kalmyk chicken and to identify the effects of polymorphism of gene markers on the exterior parameters of young animals. The object of the study is the repair young sheep reared in the farm "Arl" of the Yashkul district of the Republic of Kalmykia. The PCR-PDRF method determined the allelic spectrum of genes: calpastatin (CAST), somatotropin (GH), in young hybrids with a blood type of ? Charolais + ? Kalmyk chicken. The superiority of the CASTM allele (0.78) over the frequency of occurrence of the selectively significant CASTN allele (0.22) was noted in the calpastatin gene in crossbreed livestock. According to the growth hormone gene, molecular genetic analysis showed that the frequency of occurrence of the GHA allele in young mixed sheep was 0.88, and the frequency of occurrence of the selectively significant GHB allele was 0.12. A comparative analysis of the live weight of animals with different genotypes showed that sheep and sheep carriers of heterozygous CASTMN and GHAB genotypes have higher live weight indicators than their peers with homozygous CASTMM and GHAA genotypes. Measurements of articles of exterior and indices of physique depending on genotypes are described, since their use allows breeders to determine the type of constitution, individual characteristics, degree and proportionality of the development of the organism, age variability, condition and ability to a particular productivity.

Analysis of allelic variants in genes associated with meat productivity in regionalized small cattle breeds

The purpose of the research was to study the polymorphism of allelic variants of genes associated with high meat productivity for further selection of parental pairs using genetic methods. Genotyping of the Dagestan mountain sheep breeds (broodstock and rams) was carried out using a polymerase chain reaction. Genotyping was carried out for the following genes: CAST, GH, GDF9 on a Tertsik thermal cycler. Analysis of the results of PCR carried out with samples of sires of the Dagestan rock breed indicates that the GH gene polymorphism is represented by the A allele, with a high (0.87) and allele B, with a low (0.13) frequency of occurrence. The GDF9 gene polymorphism is represented by the GDF9G allele with a high (0.82) and the GDF9A allele with a low (0.18) frequency of occurrence. The distribution of homozygous genotype GHAA and heterozygous GHAB reached 84% and 16%, respectively. At the same time, the homozygous GHBB* genotype was absent in the studied sample. As a result of the research, new knowledge was obtained on biodiversity and forms of associations of polymorphism of the genes calpastatin, somatotropin, differential growth factor; breed-specific, population-specific features of the allelic spectrum of the CAST, GH, GDF9 genes in sheep of the Dagestan mountain sheep breed were established.

Study some Genetic Variance and Breeding Value on Productive Performance for Local Chicken Differ in Polymorphism of Growth Hormone Gene

To fix and detect some value of genetic selection parameters for hens of local chicken differ in growth hormone GH gene polymorphisms, PCR-RFLP technique used with MSP restriction enzyme, three genotype found as AA the wild, AB the heterosis and the mutant BB. Results of some genetic analysis indicating that based on breeding value BV for AA genotype was the highest one 79.913 for body weight at sexual maturity and 1.736 for average age at sexual maturity and 4.373, 5.894 and 0. 438 for average egg product at 100 days and average egg weight at 27 and 34 weeks respectively for the seam AA hens’ genotype. The lowest value for dominant deviation DD was 0.298 for traits of average first egg weight, for body weight at sexual maturity was – 6.659 and – 5.58 for average age at sexual maturity and 0.012 for average egg weight at 20 weeks and 0.042 for average egg weight at 34 weeks for hens with BB genotype. AB genotype was low in trait for average egg weight at 27 and 34 weeks with value of 8.044 and – 0.08 respectively. In conclusion molecular procedure result indicating that depending on some molecular genetic parameters RFLP for such gene of relation with productive performances and BV includes some genetic variances as DD, DV and VA and GV are good tools used in selection programs for local hen’s chicken either if their genotype is with one or two copies of allele A in order to achieve the best genetic group in the way of improving production efficiency for Iraqi local chickens.

GH and GDF9 gene polymorphisms associated with growth rate in Manych Merino sheep

GH and GDF9 gene polymorphisms associated with growth rate in Manych Merino sheep

Association of GH gene polymorphism with growth and semen traits in rabbits

<p>Although growth hormone (<em>GH</em>) gene mutations are described in several species, the studies concerning their variabilities and associations with economic traits in rabbits are scarce, particularly associations with semen traits. A total of 149 rabbit bucks from five populations (V-line=36, Moshtohor line=28, APRI line=42, cross ½A½M=23, and Gabali=20) were used in the present study to identify polymorphism of c.-78 C>T single nucleotide polymorphism (SNP) of <em>GH</em> gene among these populations and to investigate the association of <em>GH</em> gene polymorphism with body weight (BW), daily weight gain (DG) and semen traits. DNA was extracted from blood samples for genotyping of c.-78 C>T SNP of <em>GH</em> gene based on polymerase chain reaction with the restriction fragment length polymorphism (PCR-RFLP) technique. The genetic diversity of SNP C>T of <em>GH</em> gene was assessed in terms of genotypic and allelic frequencies, effective number of alleles (Ne), observed (Ho) and expected (He) heterozygosity, Hardy-Weinberg equilibrium (HWE), reduction in heterozygosity due to inbreeding (F<sub>IS</sub>) and polymorphism information content (PIC). Three genotypes of TT, CC and TC of PCR product of 231 bp of <em>GH</em> gene were detected and all the populations were in HWE in terms of <em>GH</em> gene. The highest Ne was obtained for the Moshtohor line (1.978), while the lowest allelic numbers were obtained for V-line (1.715) and Gabali breed (1.800). The highest genotype frequency of <em>GH</em> gene was 0.48 in TT genotype of V-line, 0.21 in CC genotype of Moshtohor line, 0.67 and 0.56 in TC genotype of ½A½M and Gabali rabbits (<em>P</em><0.05). The highest frequency for C allele was recorded by Moshtohor line (0.45) and the lowest frequency by Gabali (0.32). The genetic diversity scores for <em>GH</em> gene were intermediate (Ho=0.551, He=0.471, PIC=0.358). The values of Ho ranged from 0.444 in V-line to 0.667 in ½A½M cross, while the values of He were 0.425 in V-line and 0.508 in Moshtohor line. The values of PIC were moderate and ranged from 0.332 in V-line to 0.375 in M-line. The highest F<sub>IS</sub> was observed in Moshtohor line (0.042) and the lowest value was observed in ½A½M cross (–0.413). The CT genotype of <em>GH</em> gene showed the highest and significant values for body weights at 4, 8, 10 and 12 wk (542, 1131, 1465 and 1861 g) and daily gains at intervals of 4-6 and 8-10 wk (23.1 and 26.5 g). Additionally, the CT genotype recorded the highest and significant values for volume of ejaculate (1.1 mL), sperm motility (57.6%), live sperm (85.6%), normal sperm (93.1%) and sperm concentration in semen (611×106/mL), along with the lowest and significant values for dead sperms (14.4%) and abnormal sperms (6.9%).</p>

Body size characteristics and polymorphism in GH and GHRH genes of Simeulue Buffalo of Aceh, Indonesia

Eriani K, Rahmi R, Jamil I, Rosnizar R, Azhar A. 2019. Body size characteristics and polymorphism in GH and GHRH genes of Simeulue Buffalo of Aceh, Indonesia. Biodiversitas 20: 236-242. This study was done to determine body size characteristics, to identify the presence of polymorphism in the GH/MspI and GHRH/HaeIII genes, and to analyze the relationship between GH and GHRH gene polymorphisms to body size characteristics in Simeulue buffalo. Experimental animals used were 45 Simeulue buffalo randomly sampled from three subdistricts, i.e., Salang, Alafan and Simeulue Cut, fifteen from each subdistrict. Body size characteristics measured were withered height, body length, chest circumference, chest depth, and hip height. A 5 mL whole blood was collected from fifteen out of forty five by using EDTA as an anticoagulant. Extraction of genomic DNA and analysis of GH/MspI and GHRH/HaeIII polymorphisms was done using GeneAid DNA extraction kit and polymerase chain reaction-restriction length fragment polymorphism (PCR-RFLP) method, respectively. The data of body size characteristics which includes mean value, standard deviation, and coefficient of variation were analyzed descriptively. The molecular data represented by DNA banding pattern was used to calculate allele and genotype frequencies, expected (He) and observed (Ho) heterozygosities, and Hardy-Weinberg equilibrium. The relationship between genotype and body size characteristic was analyzed using t-test. The results showed that coefficient of variation in body size characteristics was low, ranging from 5.39-16.06% in the age category of 4-6 years old and ranging from 5.25-11.27% in the age category of 2- 4 years old. The results of the molecular analysis indicated that GH/MspI locus was monomorphic by the presence of one (+/+) genotype. GHRH/HaeIII locus was polymorphic as shown by the presence of 3 genotypes namely AA (0.13), AB (0.80) and BB (0.07). Expected heterozygosity (0.80) was higher than observed heterozygosity (0.49). The frequency of GHRH/HaeIII agreed with Hardy Weinberg equilibrium. GHRH/HaeIII polymorphism did not significantly influence (P>0.05) body size characteristics of Simeulue buffalo.

Association of Biometric Traits with Growth Hormone Gene Diversity in Raini Cashmere Goats

In recent years, the important effects of growth hormone on a broad variety of physiological parameters, such as lactation, reproduction, growth, and metabolism, have attracted many researchers' attentions. To detect GH gene polymorphism and its association with the biometric traits of Raini Cashmere goats, 300 animals were selected and the animals’ genotype was determined using PCR-RFLP. Two different genotypes (AA and AB) were observed in exons 2 and 3 within the goat GH gene. The genotype frequencies for AA, AB, and BB were 0.15, 0.85, and 0, and frequencies of the A and B alleles were 0.575 and 0.425, respectively. The number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected homozygosity, observed homozygosity, Nei’s index, Shannon’s index, and Fixation index (Fis) were 2, 1.96, 0.49, 0.85, 0.49, 0.51, 0.15, 0.49, 0.69, and -0.74, respectively. Birth type had a significant effect on the Chest height to earth (T26) trait (P-value = 0.032304). Furthermore, a significant effect of age on some biometric traits were observed in this study. The frequency of the AB genotype for most of the traits were higher in comparison to the AA genotype, although some traits did not show a significant effect, which might be explained by the heterosis phenomenon. According to the results, it can be concluded that allele A of growth hormone is a suitable allele for the THH (Toe height of hand hoof), THF (Toe height of foot hoof), HHF (Heel height of foot hoof), and CHE (Chest height to earth) traits, and allele B is a worthy allele for the NI (Nasal interval), LCI (Lip corner interval), NL (Neck length), CC (Chest circumference), AC (Abdominal circumference), LLF (Leg length of foot), WHC (Wither height to under the chest), and DAD (Dorsal angle distance of scapula to Hänsch point) traits. Therefore, better results in the breeding programs for these traits can be achieved from this information, along with other phenotypic records.

Investigation of Growth Hormone Releasing Hormone, Growth Hormone and Prolactin Hormone Gene Polymorphism in Anatolian Water Buffalo

Abstract The purpose of this work was to identify GHRH, GH and PRL gene polymorphisms in Anatolian water buffalo by means of the PCR-RFLP method. A total of 126 buffalo were included in this study. PCR amplification gave a 451 bp band for the GHRH gene, a 221 bp band for the GH gene and a 156 bp band for the PRL gene. The PCR products were digested by HaeIII for the GHRH gene, AluI for the GH gene and RsaI for the PRL gene. The GH/AluI and PRL/RsaI polymorphisms were found to be polymorphic, while the GHRH/HaeIII polymorphism was not found in Anatolian water buffalo. The frequencies of GH-L (0.87) and PRL-A (0.55) alleles were found to be high in the examined Anatolian water buffalo. The chi-square test showed that the Anatolian water buffalo were in Hardy-Weinberg (HW) equilibrium for the GH gene while significant deviation was observed from HW equilibrium for the PRL gene. The present study is the first to examine GHRH/HaeIII, GH/AluI and PRL/RsaI polymorphisms in Anatolian water buffalo.

Sexual dimorphism and identification of single nucleotide polymorphism of growth hormone gene in muscovy duck

This research was aimed to investigate the different growth and to identify growth hormone gene polymorphism in Muscovy ducks. Two hundred Muscovy day-old ducks consisting of white-plumed male and female duck, black and white-plumed male and female ducks. Body weight was recorded weekly and the obtained data were subject to T test. Primer design used the Custal X Program based on a database from the GeneBank Cairina moschata GH gene, partial cds (AB158762). Primer base sequence of GH gene was forward/Sequence: 5’-CTGGGGTTGTTTAGCTTGGA-3’ and reverse/Sequence: 5’-TAAACCTTCCCTGGCACAAC-3’. The DNA sequences were aligned by using the BioEdit version 7.7 for identification of the single nucleotide polymorphism. The result showed that male Muscovy duck produced higher an average body weight gain and more relative growth than those of females. The highest body weight gain was at three weeks old, and then it started to decrease at four weeks old. The sequencing PCR product obtained nucleotide polymorphism. AA genotype was observed at 136 t of black female Muscovy duck, CC in black and white male Muscovy duck, and white female Muscovy duck. Conclusively, a body weight gain of 3-week-old male Muscovy ducks was higher than that of females and GH gene polymorphism was observed in Muscovy ducks.

Association of the growth hormone gene polymorphism with growth traits in Salsk sheep breed

The aim of the study was to identify the GH/HaeIII gene polymorphism and to determine its association with growth traits in Salsk sheep bred in the Southern region of the Russian Federation. The identification of the GH gene polymorphism was performed by the PCR-RFLP method using the endonuclease HaeIII for restriction of an amplified fragment. During the experiment, the AA, AB, and BB genotypes of the Salsk breed sheep were identified at a frequency of 57, 36, and 7%, respectively. The values of the weight at weaning, at the age of 9 months and the average daily gain of the ram lamb with the AB genotype exceeded the values of the these parameters of the ram lamb with the AA genotype by 0.92kg, 10.67kg, and 47.3g, respectively. The carcass weight, the weight of meat, the slaughter weight, and the slaughter yield of the ram lamb with the AB/GH genotype were found to be more as compared with the parameters of the ram lamb with the AA/GH genotype by 4.97kg, 1.83kg, 4.83kg, and 2.04%, respectively. The ram's AB genotype also caused a greater weight of heart and kidney by 75.21 and 75.44g, respectively. Thus, the presence of a heterozygous AB genotype in Salsk sheep breed has a positive effect on the growth traits. The rams of the AB/GH genotype significantly exceeded the rams of the AA/GH genotype and were found to have the best meat productivity.

Effect of GH and DGAT1 gene polymorphism on feeding qualities of bull calves

The aim of this paper is to study effects of GH and DGAT1 gene polymorphisms on feeding qualities of Hereford and Limousin bull calves bred in conditions of the Cis-Ural steppe zone. SNPs of genes GH and DGAT1 are investigated by polymerase chain reaction (PCR) and DNA restriction fragment length polymorphism (RFLP). The studied population of animals was assessed by defining the allele frequency and animal genotype occurrence for the studied gene SNPs, indicators of the actual and expected heterozygosity, and Pearson’s test. A study of polymorphism C214G of gene GH revealed that genotype LL prevails in Hereford and Limousin animals, 47.37 and 57.7%, respectively, while frequency of allele L is higher in Limousin bull calves (0.731). A study of polymorphism K232A of gene DGAT1 gene in both the populations showed absence of genotypes AA, which can be related to the low number of the studied animals. Expected heterozygosity indicators of gene GH are higher than the observed ones, and the observed heterozygosity is higher for DGAT1. The number of efficient alleles for the studied genes is higher for Hereford bull calves. In general, according to Pearson’s test, both the studied populations are in equilibrium. There is a significant effect of GH gene polymorphism on live weight gain rates at the end of sagination and total and average daily weight gains during animal raising.

Effect of Genetic Polymorphisms in GH/Hpa II and MSTN / Dra I Loci on Body Weight in Friesian Bull Calves.

The GH and MSTN gene polymorphisms and their association with body weight were declared in a population of 100 Friesian bull calves. For DNA extraction, collection of blood samples was carried out from the studied animals. The PCR for GH and MSTN genes yielded fragments of 329 and 1346 bp, respectively. The PCR-HpaII digestion of 329 bp of GH gene revealed three genotypes: AA genotype possess undigested fragment (329 bp), AB genotype has three fragments (329, 224 and 105 bp) and BB genotype has two fragments (224 and 105 bp). The GH genotypes incidence and alleles frequency were calculated. For the 100 Friesian bull calves, genotypic frequencies for the AA, AB and BB genotypes were 0.1, 0.78 and 0.12, respectively and the allele frequencies for A and B allele frequencies were 0.49 and 0.51. Statistical analysis revealed that there was a significant effect of GH genotypes on body weight. The AB genotype possessed higher body weight than the other 2 genotypes. Regarding MSTN gene, PCR-DraI digestion of 1346 bp fragment was monomorphic; where it yielded four fragments (505, 427, 321 and 93 bp) in all animals under study. The outcome of this study is that it highlights the effectiveness of GH/HpaII locus as candidate marker for body weight in cattle rather than MSTN/DraI.

Parental contribution and growth hormone gene polymorphism associated with growth phenotypes of red sea bream Pagrus major in mass production: A case study

Red sea bream is one of the most important aquaculture fish species in Japan. To improve the productivity of this fish during seed production, improved growth traits and reduced size variation are needed. In this study, we assessed parental contribution of fast- and slow-growing individuals observed in two different rearing phases in a mass production lot: (1) 50 dph reared in a tank and (2) 200 dph reared in a net cage. We also assessed GH gene (pmaGH) polymorphisms based on a previously developed minisatellite DNA marker. Specific broodstock individuals were significantly associated with fast- or slow-growing individuals at 50 dph and 200 dph. Significant differences in pmaGH minisatellite allele frequencies were observed between fast- and slow-growing groups at 50 dph in the frequency of two alleles (pmaGH-740 and pmaGH-900, respectively). Combining the results of DNA parentage analysis and pmaGH minisatellite allele analysis, one dam and two sires, possessing pmaGH-740, were significantly associated with the slow-growing groups. These results suggest that the minisatellite marker of pmaGH could be a useful tool for growth selection of this fish species.

The relationship of GH and LEP gene polymorphisms with fat-tail measurements (fat-tail dimensions) in fat-tailed Makooei breed of Iranian sheep.

Background:The present study was designed to investigate the association of GH and LEP genes’ single-nucleotide polymorphisms with fat-tail measurements (fat-tail dimensions) in Makooei sheep.Materials and Methods:DNA was extracted from whole blood samples collected from 100 sheep. Polymerase chain reaction (PCR) products were subjected to single-strand conformation polymorphism (SSCP) denaturation and polyacrylamide gel electrophoresis. Data were collected at the Makooei Sheep Breeding Station in Makoo (36°, 35′S and 48°, 22′E) of West Azerbaijan province. Climatically, this location has temperate summers and cold winters and receives a mean annual rainfall of about 400 mm. Ewes are raised in an annual breeding cycle starting in September. In general, the flock is managed under a semi-migratory system.Results:In the tested Makooei sheep population, significant statistical results were found in all traits of fat-tail measurements for GH and LEP genes. Individuals with the G4, L4 genotype of GH and LEP genes had lower tail length (rump length), fat thickness (the thick rump), and tail width (rump width) when compared to those of individuals with other genotypes (P < 0.05). In addition, the results demonstrated that individuals with the G5, L5 genotype of GH and LEP genes had superiority of tail length (rump length) and fat thickness (the thick rump) compared to those individuals with other genotypes (P < 0.05). Individuals with the G2, L2 genotype of GH and LEP genes had superiority of tail width (rump width) compared individuals with other genotypes (P < 0.05).Conclusion:These results confirmed potential usefulness of GH and LEP genes in marker-assisted selection programs of sheep breeding.

GHR and IGF-I gene expression and production characteristics associated with GH gene polymorphism in Nile tilapia

The aim of this study was to investigate the effects of genotype on gene expression and performance characteristics in crossbred GIFT × Chitralada tilapia. We compared the effects of GH single band (GHsb) and GH double band (GHdb) genotypes on performance characteristics, growth hormone receptor (GHR) and insulin-like growth factor I (IGF-I) gene expression in the liver and white muscle. The experiment was conducted in a 2 × 2 factorial design with two categories of weight (20–35 g and 40–70 g) and two genotypes (GHsb and GHdb). Fin fragments were collected for genotyping, while the liver and white muscle samples were collected to analyze gene expression via qRT-PCR. GHdb genotype animals presented greater body weight, empty weight, weight of viscera, and filet weight and length, thereby indicating that GH variation may correlate with performance characteristics. Although some of the phenotypes we measured were correlated with genotype, we cannot say that it is due to the direct effect of the studied polymorphism. However, we recommend further studies be conducted to reveal the genetic nature of this polymorphism. • In this study a new polymorphism in GH gene was observed. • GH double band genotype animals presented the best characteristics of carcass. • GH double band genotype animals presented greater GHR mRNA expression.

黒毛和種と日本短角種の枝肉形質にCW-1，CW-2およびGHの各遺伝子多型が及ぼす影響

黒毛和種と日本短角種の枝肉形質にCW-1，CW-2およびGHの各遺伝子多型が及ぼす影響

Study of the correlation between GH gene polymorphism and growth traits in sheep.

The growth hormone gene plays an important role in the physiological function of an organism. The current study aimed to investigate the correlation between polymorphisms in the 5' regulatory region, exon 4, and 3' untranslated region (UTR) of the sheep GH gene and sheep growth traits. The DNA from 510 adult sheep was analyzed by DNA sequencing and polymerase chain reaction single-strand conformation polymorphism. Two alleles (A and B) and 3 genotypes (AA, AB, and BB), 2 alleles (A and B) and 3 genotypes (AA, AB, and BB), and 3 alleles (A, B, and C) and 4 genotypes (AA, AB, BB, and AC) were found within the 5' regulatory region, exon 4, and 3' UTR, respectively. In Tibetan sheep, the association analysis indicated that there were statistically significant differences in the scores of weight, length, and heart girth within the 5' regulatory region; weight, length, wither height, and heart girth within exon 4; and weight, length, wither height, and heart girth within the 3' UTR among the different genotypes. For exon 4, Poll Dorset sheep individuals with genotype AA showed a lower score than those of genotypes BB and AB (P<0.05). With regard to the 3' UTR, Poll Dorset sheep with genotype AC showed higher scores than those of genotypes AA and AB (P<0.05).