Single nucleotide polymorphism in growth hormone gene exon-4 and exon-5 using PCR-SSCP in Black Bengal goats - A prolific meat breed of India

Growth, haemato-biochemical, hormonal and disease characteristics in Black Bengal goats: a review

The goats have been considered one of the noteworthy animals to provide food security and could promote socio-economic upliftment under challenging climatic scenarios in the coming decades, particularly in the tropics. Black Bengal goat (BBG) is one of the recognised native meat-type breeds of hot-humid tropics with distinguished characteristics, including superior-quality meat, excellent skin and high prolificacy. Smaller body mass, lower metabolic rate and efficient utilisation of high-fibre forages enable BBG to adapt to a wide range of harsh climates in the tropics. The BBG can maintain physiological homeostasis efficiently in terms of electrolyte profile, endocrine functions and haemato-biochemical traits in different life phases, including the gestation period, even in high-saline coastal areas of hot-humid tropics. Crossbreeding to improve its growth rate has been attempted, but the prolificacy has been decayed. This review is intended to attract global attention to the adaptive potentialities of Black Bengal goats in terms of growth and production, haemato-biochemical, endocrinological, salt tolerance and disease characteristics that could be an asset of climate-resilient agricultural farming.

Morphometric features and performances of Black Bengal goat in Bangladesh

Black Bengal goat (BBG) is the most adaptable, widely distributed, and prominent goat breed in Bangladesh, well known in the world for its high prolificacy, low demand of feed, tolerance to harsh weather conditions, and disease resistance with remarkably good quality red meat and skin. A large number of indiscriminate research reports on BBG have been published; however, the review on the productive and reproductive performances with different physiological features of BBG in Bangladesh is scarce. This review was conducted to investigate and summarize the available research reports on BBGs to highlight the gaps and provide coherent recommendations for the future research plan for sustainable BBG production in Bangladesh. It covers research works in morphometric features, feeding and nutrition, reproduction, diseases and health management, husbandry practices, and production performances of BBG under local conditions. Due to the contemporary increased demand for animal protein (meat and milk), the scope of small ruminants, especially goat farming, increases with other large ruminants farming. The key constraints of BBG production in Bangladesh include higher disease prevalence with low or no management practices, kid mortality, inadequate feeds and fodder supply, and poor marketing channel with some other stumpy genetic potentialities (slower body weight gain, low milk production) of this goat. Future research would be required to assess the contribution of BBG to household economies and food securities throughout the year and evaluate the constraints, adaptation and extension of artificial insemination (AI), and genetic improvement of economically important traits using molecular techniques and the selective breeding program.

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.

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.

Comparative sequence analysis in the exon 5 of growth hormone gene in the various livestock species of India

The aim of the study was to identify genetic polymorphism in growth hormone (GH) gene locus of six different livestock species using PCR-Direct DNA sequencing method. In exon 5 of GH gene, 10 SNPs variants were identified in all livestock species studied, namely Bubalus bubalis, Bos indicus, Bos frontalis, Bos grunniens, Ovis aries, and Capra hircus. Four SNPs were observed in Bubalus bubalis, two SNPs in Bos indicus, one SNP in Ovis aries, and three SNPs in Capra hircus. No changes were observed in Bos grunniens and Bos frontalis when compared with the template sequence and the SNPs observed in the present investigation may be useful in the marker assisted selection.

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.

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.

Identification of SNPs within the sheep PROP1 gene and their effects on wool traits

Regarding mutations of PROP1 (Prophet of POU1F1) gene significantly associating with combined pituitary hormone deficiency (CPHD) in human patients and animals, PROP1 gene is a novel important candidate gene for detecting genetic variation and growth, reproduction, metabolism traits selection and breeding. The aim of this study was to detect PROP1 gene mutation of the exon 1-3 and its association with wool traits in 345 Chinese Merino sheep. In this study, on the basis of PCR-SSCP and DNA sequencing methods, ten novel SNPs within the sheep PROP1 gene, namely, AY533708: g.45A>G resulting in Glu15Glu, g.1198A>G, g.1341G>C resulting in Arg63Ser, g.1389G>A resulting in Ala79Ala, g.1402C>T resulting in Leu84Leu, g.1424A>G resulting in Asn91Ser, g.1522C>T, g.1556A>T, g.1574T>C, g.2430C>G were reported. In addition, association analysis showed that three genotypes of P4 fragment were significantly associated with fiber diameter in the analyzed population (P=0.044). These results strongly suggested that polymorphisms of the PROP1 gene could be a useful molecular marker for sheep breeding and genetics through marker-assisted selection (MAS).

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.