Polymorphisms at the five exons of the growth hormone gene in the algarvia goat: possible association with milk traits

The effect of insulin-like growth factor 1 receptor gene single nucleotide polymorphism on growth and milk production traits in two native Indian tropical goat breeds

Insulin like growth factor1(IGF-1) is an essential growth factor that mediates the growth-promoting functions of pituitary growth hormone. Insulin like growth factor 1 receptor (IGF1R) is a tyrosine kinase receptor that mediates the actions of IGF1. Therefore, IGF1R is a candidate gene for examining SNPs linked with growth and production traits. The objective of this study was to detect the c.546 + 179170A > T transversion in intron 2 of the gene encoding IGF1R in two goat breeds, Attappady Black and Malabari, and examine the association of this polymorphism with growth and milk production. For the identification of the SNP, the T-ARMS-PCR was utilized. All three genotypes were present in the two investigated breeds. The polymorphism was found to be significantly (p < 0.05) linked with growth traits. At birth, 3 and 6 months of age, Attappady goats with the AT genotype had significantly (p < 0.05) higher body weights than those with the AA and TT genotypes. Malabari goats with the AT genotype had significantly (p < 0.05) higher body weights at birth and at 3 months of age. The genotypes of the IGF1R gene had no effect on total or peak milk production. Therefore, this SNP could be used as a molecular marker in selection of meat-producing goat breeds.HIGHLIGHTSc.546 + 179170A > T IGF1R transversion was detected using T-ARMS-PCR in two indigenous goat breeds from Kerala.Attappady Black and Malabari goat breeds of Kerala possessed all the three genotypesIn these breeds, there was a significant correlation between this SNP, c.546 + 179170A > T IGF1R, and body weight.In both the breeds, there was no association between this SNP and milk production traits.

Milk-y Way: the impact of single-nucleotide polymorphisms on milk production traits in Kilis dairy goats

This study aimed to investigate the impact of single-nucleotide polymorphisms (SNPs) on milk production traits in Kilis dairy goats by analyzing the genotypes of POU1F1, PRLR, β -Lg, GH1, and GH2 genes and their association with lactation milk yield (LMY), lactation length (LL) and average daily milk yield (ADMY). Blood samples were collected from 227 goats, and genotyping was performed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). The results revealed that the frequencies of the genotypes varied among the genes. The polymorphisms were found to be significantly linked with milk production traits. These findings suggest that SNPs of POU1F1/AluI, PRLR/RsaI and β -Lg/SacII are significantly associated with LMY and that the POU1F1-TC genotype, PRLR-TT genotype and β -Lg-AB genotype are associated with higher LMY and ADMY. Additionally, the POU1F1-TC genotype was found to have a longer LL. However, no significant association was found between the GH1 and GH2 genotypes and LMY, LL and ADMY. Overall, this study provides valuable insights into the genetic factors influencing milk production traits in Kilis dairy goats, which can be utilized for the selection of high-yielding animals in breeding programs.

The growth hormone gene polymorphism and its relationship to performance and carcass features in Egyptian Awassi lambs

The main purpose of the existing experiment was to assess the allelic and genotypic polymorphisms of the Growth hormone (GH) gene and its correlation with growth indices, efficiency of consumed feed, some body indices and carcass traits of the Egyptian Awassi sheep. Forty Egyptian Awassi male lambs were selected for their growing indices (post-weaning daily gain, marketing weight, and weaning weight), feed efficiency (consumed feed and of consumed feed), body conformational indicators (skeletal muscle index, relative body index, body mass index, and body index), and carcass features (dressing %, hot carcass weight, fore-legs %, neck %, loin %, ribs %, abdominal fat %, Tail % and hind-legs %). The polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) tool was applied to detect the genotypic and allelic GH gene polymorphisms properties. The PCR-RFLP analysis identified three main genotypes (AA, AB and BB) and two main alleles (A and B). The GH genotype (AA or AB) exhibited moderate significant influence (P < 0.05) on marketing weight, Loin% and Tail%. Also, genotype (AB or BB) of expressed GH gene significantly (P < 0.01) influence on consumed feed, post-weaning daily gain, neck% and body mass index, whereas, it had no influence on the phenotypic values of the other characteristics investigated. The presence of the A allele in the genotype was markedly associated (P < 0.01) with consumed feed, body mass index and post-weaning daily growth; conversely, the presence of the B allele in the genotype was significantly related (P < 0.05) with marketing weight, loin %, and tail %. While, GH gene expression was revealed to be highly significant (P < 0.01) in relation to post-weaning daily growth, feed intake, and neck %. According to the findings, determining the associations between GH gene variation and growth, efficiency of consumed feed, body measurements, and carcass features of Egyptian Awassi sheep and applying marker assisted selection with the GH gene to improve these traits is warranted and will be of significant economic value to sheep production.

Polymorphisms of the growth hormone gene and their association with growth traits and sex in Sarcocheilichthys sinensis

The growth hormone gene (gh) of Sarcocheilichthys sinensis was cloned and characterized in this study. The cDNA length of gh was 973 bp, containing a 5'-UTR of 15 bp, a 3'-UTR of 325 bp and an open reading frame of 633 bp. The genomic DNA of gh was 2135 bp in length containing five exons and four introns. The precursor peptide of gh contained 210 amino acids (aa), including a signal peptide of 22 aa (Met¹-Ala²²) and a mature region of 188 aa (Ser²³-Leu²¹⁰). The similarity and identity ranges of the gh precursor peptide with those of other cyprinids were 88.6%-99.0% and 84.8%-98.6%, respectively. The gh of S. sinensis expressed at the highest level in the pituitary, and its expression was also detected in muscle and brain. Six polymorphic sites were detected in intron 1 (g.51InDel, g.64InDel and g.242InDel), intron 2 (g.864T>C), intron 3 (g.1017InDel) and intron 4 (g.1541A>G). Among these sites, g.242InDel was significantly associated with condition factor, g.1541A>G was associated with all six growth traits, while g.864T>C was associated with sex. The data obtained herein provide useful information for further studies on the regulation mechanisms of growth and sexual growth differences in S. sinensis.

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

BACKGROUND

Identification of molecular characterization of genes underlying livestock productive traits may allow applying advanced biotechnology techniques to improve animal productivity. Growth hormone (GH) controls body growth rate, milk production, reproduction as well as carbohydrate, lipid, and protein metabolism. Therefore, the present study aims to investigate the genetic variations of growth hormone cDNA sequences between Assaf sheep (As_GH) and Boer goat (Bo_GH) that mainly used for genetic improvement in Egypt using bioinformatics analysis. Growth hormone cDNA was isolated from the pituitary gland tissue of Assaf sheep Boer goat and subcloned into pTZ57R/T cloning vector for sequencing.

RESULTS

Molecular weight of As_GH cDNA was 665 bp and was 774 bp for Bo_GH cDNA. The complete coding sequences (CDS) of As_GH and Bo_GH were registered in the GenBank database under accession number (AC: MH128986 and AC: MG744290, respectively). High homology percentage was observed (99.5%) between AS_GH and Bo_GH protein sequences with one different amino acid in the As_GH protein sequence (Arg194). The protein sequence of As_GH has only one motif signature; Somatotropin_1 from 79 to 112 aa compared to Bo_GH protein sequences and GenBank database that had two motifs signature. The growth hormone cDNA sequence of Assaf sheep has a unique three single nucleotide polymorphisms (SNPs) (A637A638G639) that encodes for arginine (Arg194); this insertion mutation (AAG) was not found in the growth hormone cDNA sequences of Boer goat in the present study and GenBank database breeds. This mutation can be used to develop SNPs markers for Assaf sheep.

CONCLUSIONS

GH sequence of Assaf and Boer goat is highly conserved and the homogeny in the codon region (99.5%). The Assaf sheep GH sequence has a unique three SNPs that may be used to develop SNPs markers for such breed. Further studies are needed to investigate the genetic variations of growth hormone gene in different sheep and goat breeds in Egypt and document the relationship between these variations and the productive performance of animals.

Effect of growth hormone gene polymorphism on growth traits in migratory Gaddi goats of Western Himalayas, India

Goat production under migratory system is foremost meat resource in Western Himalayan region of India. Thus, selection of goats for superior growth rate is rewarding. Growth hormone (GH) gene is identified as main regulator of post-natal growth and development. The objective of this study was to identify GH gene variants in Gaddi goats reared under migratory system via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and single-strand conformation polymorphism (SSCP). Blood samples from 63 animals from different migratory flocks registered under All India Coordinated Research Project, Himachal Pradesh Agricultural University (HPAU), Palampur, were subjected to DNA isolation. A total of 422, 116, 389 and 181-bp amplicons were generated on amplification of four targeted regions of GH gene. GH1 and GH2 fragments were analysed using PCR-RFLP (HaeIII RE) that revealed three variants (AA, AB and BB) for GH1 having frequency as 0.27, 0.52 and 0.31, respectively whereas, two variants (AB and BB) were revealed for GH2 fragment having frequency of 0.24 and 076, respectively. GH3 and GH4 fragments were subjected to PCR-SSCP that detected three genotypes (AB, BB and AA) for GH3 with respective genotype frequency as 0.57, 0.21 and 0.22 respectively; however, GH4 was found to be monomorphic. The polymorphism information content values for GH1, GH2 and GH3 were 0.37, 0.36 and 0.34, respectively, which suggested the median level of polymorphism at studied loci and also indicated the effectiveness of the studied marker for population genetic studies. Significant associations (P ≤ 0.05) were detected for GH1 with 9-month body weight, GH2 with 9 and 12-month heart girth and GH3 with 6-month body weight, body height and body length, respectively. From the present study, it was concluded that SNPs and their association with some body measurements may be employed as useful markers for ongoing phenotypic selection programme.

Genome-wide association study of conformation and milk yield in mixed-breed dairy goats

Identification of genetic markers that affect economically important traits is of high value from a biological point of view, enabling the targeting of candidate genes and providing practical benefits for the industry such as wide-scale genomic selection. This study is one of the first to investigate the genetic background of economically important traits in dairy goats using the caprine 50K single nucleotide polymorphism (SNP) chip. The aim of the project was to perform a genome-wide association study for milk yield and conformation of udder, teat, and feet and legs. A total of 137,235 milk yield records on 4,563 goats each scored for 10 conformation traits were available. Out of these, 2,381 goats were genotyped with the Illumina Caprine 50K BeadChip (Illumina Inc., San Diego, CA). A range of pseudo-phenotypes were used including deregressed breeding values and pseudo-estimated breeding values. Genome-wide association studies were performed using the multi-locus mixed model (MLMM) algorithm implemented in SNP & Variation Suite v7.7.8 (Golden Helix Inc., Bozeman, MT). A genome-wise significant [-log₁₀(P-value) > 5.95] SNP for milk yield was identified on chromosome 19, with additional chromosome-wise significant (-log₁₀(P-value) > 4.46] SNP on chromosomes 4, 8, 14, and 29. Three genome-wise significant SNP for conformation of udder attachment, udder depth, and front legs were identified on chromosome 19, and chromosome-wise SNP were found on chromosomes 4, 5, 6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 21, 23, and 27. The proportion of variance explained by the significant SNP was between 0.4 and 7.0% for milk yield and between 0.1 and 13.8% for conformation traits. This study is the first attempt to identify SNP associated with milk yield and conformation in dairy goats. Two genome-wise significant SNP for milk yield and 3 SNP for conformation of udder attachment, udder depth, and front legs were found. Our results suggest that conformation traits have a polygenic background because, for most of them, we did not identify any quantitative trait loci with major effect.

Targeted high-throughput growth hormone 1 gene sequencing reveals high within-breed genetic diversity in South African goats

This study assessed the genetic diversity in the growth hormone 1 gene (GH1) within and between South African goat breeds. Polymerase chain reaction-targeted gene amplification together with Illumina MiSeq next-generation sequencing (NGS) was used to generate the full length (2.54 kb) of the growth hormone 1 gene and screen for SNPs in the South African Boer (SAB) (n = 17), Tankwa (n = 15) and South African village (n = 35) goat populations. A range of 27-58 SNPs per population were observed. Mutations resulting in amino acid changes were observed at exons 2 and 5. Higher within-breed diversity of 97.37% was observed within the population category consisting of SA village ecotypes and the Tankwa goats. Highest pairwise FST values ranging from 0.148 to 0.356 were observed between the SAB and both the South African village and Tankwa feral goat populations. Phylogenetic analysis indicated nine genetic clusters, which reflected close relationships between the South African populations and the other international breeds with the exception of the Italian Sarda breeds. Results imply greater potential for within-population selection programs, particularly with SA village goats.

Polymorphisms and DNA methylation level in the CpG site of the GHR1 gene associated with mRNA expression, growth traits and hormone level of half-smooth tongue sole (Cynoglossus semilaevis)

The objectives of the present study were to estimate the GHR1 gene mutations and methylation status of CpGs, and whether those mutations and methylation were involved in the regulation of GHR1 gene expression, hormone level and growth traits in half-smooth tongue sole (Cynoglossus semilaevis). Identification of single-nucleotide polymorphisms was performed on 43 male fish. Through polymerase chain reaction-single-strand conformation polymorphism and sequencing, two SNPs were found. SNP1 [c.G1357A (p.Val376Ile)] creating one CpG site located in exon 8 was named L1 locus, and SNP2 (c.G1479A) located in exon 9 was named L2 locus. Individuals were divided into three genotypes, AA, AG and GG according to L1 locus (GG genotype had one more CpG site because of the mutation), and into two genotypes, AA- and GG-based on L2 locus. The results showed that only L1 locus was significantly associated with body weight (P < 0.01), gonad weight (P ≤ 0.05), triiodothyronine (T3) level (P ≤ 0.05) and mRNA expression (P < 0.01). At L1 locus, newly created CpG site in GG genotype was highly methylated (93.3 %), while there was no difference of methylation level in the other two CpG sites among three genotypes. AA genotype and AG genotype having higher T3 level were significantly different (P ≤ 0.05) from GG genotype. There were significant differences among body weights of AA, AG and GG genotypes (P < 0.01). Gonad weights of AA genotype and AG genotype were significantly lower than GG genotype. The GHR1 mRNA expression of GG genotype was significantly lower than AA and AG genotypes (P < 0.01). These implied that mutations and methylation status of GHR1 gene might influence the hormone level, growth traits and gene expression in male half-smooth tongue sole and the L1 locus could be regarded as a potential candidate genetic and epigenetic marker in half-smooth tongue sole selection.

The sheep growth hormone gene polymorphism and its effects on milk traits

Growth hormone (GH) is encoded by the GH gene, which may be single copy or duplicate in sheep. The two copies of the sheep GH gene (GH1/GH2-N and GH2-Z) were entirely sequenced in one 106 ewes of Sarda breed, in order to highlight sequence polymorphisms and investigate possible association between genetic variants and milk traits. Milk traits included milk yield, fat, protein, casein and lactose percentage. We evidenced 75 nucleotide changes. Transcription factor binding site prediction revealed two sequences potentially recognised by the pituitary-specific transcription factor POU1FI at the GH1/GH2-N gene, which were lost at the promoter of GH2-Z, which might explain the different tissues of expression of GH1/GH2-N (pituitary) and GH2-Z (placenta). Significant differences in milk traits were observed among genotypes at polymorphic loci only for the GH2-Z gene. Sheep with homozygote genotype ss748770547 CC had higher fat percentage (P < 0·01) than TT. SNP ss748770547 was part of a potential transcription factor binding site for C/EBP alpha (CCAAT/Enhancer Binding Protein), which is involved in the regulation of adipogenesis and adipoblast differentiation. SNP ss748770547, located in the GH2-Z gene 5′ flanking region, may be a causal mutation affecting milk fat content. These findings might contribute to the knowledge of the sheep GH locus and might be useful in selection processes in sheep.

The association between polymorphism of the GH1 gene and changes in protein structure and carcass traits in Mehraban sheep (Ovis aries)

The present study indicates an association between carcass traits and genetic polymorphism and changes in the protein structure of the growth hormone 1 (GH1) gene in Mehraban sheep. Polymorphism of the GH1 gene was detected by polymerase chain reaction–single strand conformation polymorphism (PCR–SSCP) and DNA sequencing methods in 463 individuals. Two different structures in the GH1 protein and six single nucleotide polymorphisms were identified. The association of these SSCP patterns and protein structures with carcass traits was analysed. The SSCP patterns were shown to be associated with carcass traits. Individuals with AB SSCP pattern and Type B protein structure had significantly higher fat-tail weight and volume (P < 0.05) than did those individuals with CC SSCP pattern and Type A protein structure. Moreover, CC SSCP pattern and Type A protein structure contributed to low concentration of blood triglycerides (P = 0.004). The results confirmed the importance of GH1 as a candidate gene for marker-assisted selection for carcass-trait variations in sheep.

The Application of Genomic Technologies to Investigate the Inheritance of Economically Important Traits in Goats

Goat genomics has evolved at a low pace because of a lack of molecular tools and sufficient investment. Whilst thousands and hundreds of quantitative trait loci (QTL) have been identified in cattle and sheep, respectively, about nine genome scans have been performed in goats dealing with traits as conformation, growth, fiber quality, resistance to nematodes, and milk yield and composition. In contrast, a great effort has been devoted to the characterization of candidate genes and their association with milk, meat, and reproduction phenotypes. In this regard, causal mutations have been identified in the αS1-casein gene that has a strong effect on milk composition and the PIS locus that is linked to intersexuality and polledness. In recent times, the development of massive parallel sequencing technologies has allowed to build a reference genome for goats as well as to monitor the expression of mRNAs and microRNAs in a broad array of tissues and experimental conditions. Besides, the recent design of a 52K SNP chip is expected to have a broad impact in the analysis of the genetic architecture of traits of economic interest as well as in the study of the population structure of goats at a worldwide scale.

Genetic polymorphisms and protein structures in growth hormone, growth hormone receptor, ghrelin, insulin-like growth factor 1 and leptin in Mehraban sheep

The somatotropic axis, the control system for growth hormone (GH) secretion and its endogenous factors involved in the regulation of metabolism and energy partitioning, has promising potentials for producing economically valuable traits in farm animals. Here we investigated single nucleotide polymorphisms (SNPs) of the genes of factors involved in the somatotropic axis for growth hormone (GH1), growth hormone receptor (GHR), ghrelin (GHRL), insulin-like growth factor 1 (IGF-I) and leptin (LEP), using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods in 452 individual Mehraban sheep. A nonradioactive method to allow SSCP detection was used for genomic DNA and PCR amplification of six fragments: exons 4 and 5 of GH1; exon 10 of GH receptor (GHR); exon 1 of ghrelin (GHRL); exon 1 of insulin-like growth factor-I (IGF-I), and exon 3 of leptin (LEP). Polymorphisms were detected in five of the six PCR products. Two electrophoretic patterns were detected for GH1 exon 4. Five conformational patterns were detected for GH1 exon 5 and LEP exon 3, and three for IGF-I exon 1. Only GHR and GHRL were monomorphic. Changes in protein structures due to variable SNPs were also analyzed. The results suggest that Mehraban sheep, a major breed that is important for the animal industry in Middle East countries, has high genetic variability, opening interesting prospects for future selection programs and preservation strategies.

Sequence polymorphisms at the growth hormone GH1/GH2-N and GH2-Z gene copies and their relationship with dairy traits in domestic sheep (Ovis aries)

The purpose was to analyze the growth hormone GH1/GH2-N and GH2-Z gene copies and to assess their possible association with milk traits in Sarda sheep. Two hundred multiparous lactating ewes were monitored. The two gene copies were amplified separately and each was used as template for a nested PCR, to investigate single strand conformation polymorphism (SSCP) of the 5'UTR, exon-1, exon-5 and 3'UTR DNA regions. SSCP analysis revealed marked differences in the number of polymorphic patterns between the two genes. Sequencing revealed five nucleotide changes at the GH1/GH2-N gene. Five nucleotide changes occurred at the GH2-Z gene: one was located in exon-5 (c.556G > A) and resulted in a putative amino acid substitution G186S. All the nucleotide changes were copy-specific, except c.*30delT, which was common to both GH1/GH2-N and GH2-Z. Variability in the promoter regions of each gene might have consequences on the expression level, due to the involvement in potential transcription factor binding sites. Both gene copies influenced milk yield. A correlation with milk protein and casein content was also evidenced. These results may have implications that make them useful for future breeding strategies in dairy sheep breeding.

Growth hormone gene variability and its effects on milk traits in primiparous Sarda goats

The aim of this research was to investigate variability in each of the five exons of the caprine growth hormone (gGH) gene, in order to establish the possible relationships with milk traits in Sarda breed goat. The general linear model procedure was used to analyse the effects of the single strand conformation (SSCP) profiles on milk traits of 100 lactating goats. Analysis of conformational polymorphism at exons 1–5 revealed a total of 25 differing banding patterns. Sequencing revealed 21 nucleotide changes (compared with GenBank D00476): 14 were polymorphic and 7 monomorphic; 19 in exonic regions, 5 of which were nonsynonymous. A SNP upstream of the transcription initiation codon (c.-3A>G) and an indel (c.*29_30insC) in the 3′UTR, were detected. Alignment of 4 cloned sequences including the entire gGH gene led to the identification of 22 nucleotide variations within the intron regions, including two indels. Association analysis revealed that each exon, except exon-1, affected milk yield, exons 1 and 3 influenced milk fat percentage, and all exons, except exon-2, had an effect on protein percentage, supporting previous results in livestock. The variability detected at the caprine GH gene might provide useful information for the phylogeny of ruminants and, more importantly, have implications on the biological function of the growth hormone and on those traits resulting from its physiological action, including milk production and composition. The caprine GH gene may become a useful molecular marker for a more effective genetic selection for milk production traits in goats.

PCR-SSCP variation of GH and STAT5A genes and their association with estimated breeding values of growth traits in Baluchi sheep

Growth hormone (GH) selected for its important role in economically relevant traits and signal transducers and activators of transcription 5A (STAT5A) is also known as a main mediator of growth hormone action on target genes. A total number of 190 lambs of Iranian purebred Baluchi sheep were genotyped at exon 5 of GH and exons 7 and 8 of STAT5A genes by using PCR-SSCP analysis. GH gene revealed three (G1, G2, and G3) conformational patterns; however, STAT5A loci were not polymorphic. Breeding values of growth traits including birth weight, weaning weight, 6 months weight, 9 months weight, and yearling weight were estimated by using the Best Linear Unbiased Prediction based on an animal model with a relationship matrix. Studied growth traits were examined for association analysis. Our findings suggest that animals with G2 genotype have highest breeding value for six month weight, while these animals have lowest breeding value for pre-weaning traits. Higher performance of G2 animals in adult ages may be related to the growth hormone role in puberty ages. The other traits showed no relationship to the genotypes examined.

The association of two single nucleotide polymorphisms (SNPs) in growth hormone (GH) gene with litter size and superovulation response in goat-breeds

Two active mutations (A 781 G and A 1575 G) in growth hormone (GH) gene, and their associations with litter size (LS), were investigated in both a high prolificacy (Matou, n = 182) and a low prolificacy breed (Boer, n = 352) by using the PCR-RFLP method. Superovulation experiments were designed in 57 dams, in order to evaluate the effect of different genotypes of the GH gene on superovulation response. Two genotypes (AA and AB, CC and CD) in each mutation were detected in these two goat breeds. Neither BB nor DD homozygous genotypes were observed. The genotypic frequencies of AB and CC were significantly higher than those of AA and CD. In the third parity, Matou dams with AB or CC genotypes had significantly larger litter sizes than those with AA and CD (p < 0.05). On combining the two loci, both Matou and Boer dams with ABCD genotype had the largest litter sizes when compared to the other genotypes (p < 0.05). When undergoing like superovulation treatments, a significantly higher number of corpora lutea and ova, with a lower incidence of ovarian cysts, were harvested in the AB and CC genotypes than in AA and CD. These results show that the two loci of GH gene are highly associated with abundant prolificacy and superovulation response in goat breeds.

Novel polymorphisms of the growth hormone gene and their effect on growth traits in Chinese goats

The polymorphisms of the growth hormone (GH) gene were analyzed in 686 individuals from four goat populations, Three haplotypes (A, B and C) and three observed genotypes (AA, AB and AC) were detected at the P2 locus, and three haplotypes (E, F and G) and three observed genotypes (EE, EF and EG) were also detected at the P4 locus. In addition, five single nucleotide polymorphisms (SNPs)-A112G, C142T (Gly>Ser), C214T (P2 locus), C266A (Pro>His) and C214T (P4 locus, Arg>Trp), were identified by GH gene sequencing and PCR-SSCP analysis. The SNPs loci were in Hardy-Weinberg disequilibrium in three goat populations (P<0.05). Association of polymorphisms with growth traits was done in BG, F1 and F1 populations, which were shown to be associated with growth traits in three goat populations. The SNPs in the goat GH gene had significant effects on growth traits (P<0.05). suggesting that the GH gene is a strong candidate gene that affects growth traits in goat.

A novel missense (A79V) mutation of goat PROP1 gene and its association with production traits

As a paired class homeodomain transcription factor, mutations of PROP1 (Prophet of POU1F1) are responsible for deficiencies of GH, PRL, TSH, LH and FSH. Regarding mutations of GH, PRL, and POU1F1 genes significantly associating with different production traits, PROP1 gene is a novel important candidate gene for detecting genetic variation and association analysis in marked-assist selection (MAS) program. Therefore, the objective of this study is to detect goat PROP1 gene mutation and its association with production traits. Herein, a novel mutation (AF453512:g.1795C>T) within PROP1 gene is revealed by PCR-SSCP and DNA sequencing methods, and genotyped by Hin6I PCR-RFLP method in 1,344 individuals belonging to eight goat breeds. Only two genotypes (CC and CT) are revealed and the frequencies of allele C go from 0.9014 to 1.000 in analyzed populations. The genetic diversity analysis reveals that all PIC values are less than 0.1619, implying that the Hin6I locus within PROP1 gene possesses low genetic diversity in goat. Furthermore, nucleotide sequence analysis shows that AF453512:g.1795C>T results in a missense amino acid (A79V). But, association analysis demonstrates no significant differences between different genotypes and production traits (such as body weight, cashmere yield, fiber length and wool thickness) of Inner Mongolia White Cashmere goat (P > 0.05), as well as no significant relationship between different genotypes and average milk yield (P > 0.05). Although Hin6I polymorphism can not be used as a molecular marker for production traits in MAS, the present work presents preliminary novel missense mutation which extends the spectrum of genetic variations of goat PROP1 gene and may benefit for considering its association with other biophysical and biochemical indexes.

Polymorphism of the growth hormone gene and its association with growth traits in Boer goat bucks

In the present study, the polymorphism of growth hormone (GH) gene was analyzed as a genetic marker candidate for growth traits in Boer goat bucks. Two single nucleotide polymorphisms (SNPs) - A781G (Ser/Gly35) and A1575G (Leu147), were identified by GH gene sequencing and PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) analysis. AA genotype resulted in a significant decrease in birth chest girth (P=0.03) and weaning weight (P=0.014) comparing to AB genotype, while CC genotype contributed to weaning height (P=0.04) greater than CD genotype. When in combination, AACD genotype was undesired for lower scores in a series of growth traits including body weight, length, height, and chest girth at birth and weaning, as well as the pre-weaning daily gain and body weight at age of 11 months. These results indicate that new molecular markers associated with caprine growth traits can be used in MAS (marker-assisted selection) in Boer goat bucks.

Identification of Avai polymorphisms in the third intron of GH gene and their associations with abdominal fat in chickens

Growth hormone (GH) plays a diverse role in animals together with other hormones of somatotropic axis. In the current research, chicken GH (cGH) as a candidate gene affecting carcass traits was investigated in the chickens from 2 local chicken breeds [Mountainous Black-Bone (Wugu) and Caoke chicken] in the Sichuan province, 1 pure line of a quality chicken (Sanhuang chicken) from the Guangdong province, and commercial crossbreds. The RFLP method was used to identify polymorphisms of the cGH gene. Three restriction enzyme polymorphic sites were detected in the cGH gene. Sequence alignment from GenBank revealed 2 mutations in the third intron of the cGH gene, which were identified by the AvaI enzyme. Two novel AvaI polymorphic sites were genotyped in 240 chickens from the above-mentioned chicken populations. One EcoRV polymorphic site, the previously reported polymorphism, was also detected in these populations. Significant differences in allelic and genotypic frequencies among all the chicken populations were observed. In AvaI polymorphic sites, allele A2 and B1 had higher frequencies than allele A1 and B2, respectively. In EcoRV polymorphic sites, the frequency of allele N2 was higher than that of allele N1. Associations of polymorphisms of the cGH gene with carcass traits were analyzed by using a GLM procedure. Significant associations were found between AvaI genotypes or combined genotypes and abdominal fat weight and abdominal fat percentage (P<or=0.05). The allele A2 and B1 had a beneficial effect on increasing the live BW, breast muscle weight, and breast muscle percentage while decreasing the abdominal fat weight, abdominal fat percentage, and s.c. fat thickness. No significant associations were observed between EcoRV genotypes and carcass traits. In conclusion, the cGH gene may be a potential marker affecting the abdominal fat trait of chickens.

Growth hormone expression in the perinatal and postnatal rat lung

It is now established that the lung is a target site for pituitary growth hormone (GH) action, because pathophysiological states of pituitary GH excess and deficiency are associated with impaired pulmonary function. The onset of lung development and differentiation is, however, before the ontogenic differentiation of pituitary somatotrophs. GH may be involved, nevertheless, in lung development, because it is present in extrapituitary tissues of preimplantation mouse embryos and in the lung buds of embryonic chickens. The possibility that GH may be expressed in the rat lung during fetal and neonatal development, therefore, has been assessed. GH mRNA was detected in the lung, and its 693-bp sequence was identical to that in the pituitary gland. By in situ hybridization, this transcript was found to be abundantly expressed in the lungs of embryonic day (ED) 17 rats in mesenchymal, mucosal epithelial, and smooth muscle cells. This transcript was expressed in neonates until at least day 14 postnatally and was localized to type I and II epithelial cells and to pulmonary tissue macrophages and alveolar macrophages. GH immunoreactivity paralleled GH mRNA cellular localization throughout the time course studied. This immunoreactivity was specific and was lost after antibody preabsorption. The perinatal and postnatal lung is, therefore, an extrapituitary site of GH gene expression during development. Given that the GH receptor is present in the lung from early development, lung GH may have autocrine and/or paracrine roles in lung growth or differentiation or in pulmonary function.