Association of IGF-I gene polymorphisms with milk yield and body size in Chinese dairy goats

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.

Association of PRLR, IGF1, and LEP genes polymorphism with milk production and litter size in Egyptian Zaraibi goat

Studying variation in genes responsible for physiological characters is important to enhance goat productive and reproductive efficiency. This study aimed to detect specific nucleotide polymorphisms in prolactin receptor (PRLR), insulin-like growth factor (IGF1), and leptin (LEP) genes and their correlation with milk production (MP) and litter size (LS) traits in Zaraibi goat. PCR-SSCP products of different patterns of each gene were sequenced and aligned to reveal two mutations (T > C) and (G > A) in 3′UTR of PRLR gene and registered on NCBI with accession numbers OM418863 for TT and OM418864 for CT, while (G > A) variation was registered as OM418861 for GG and OM418862 for AG in exon 10. TT, CT, AG, and GG genotypes were distributed in the studied animals with frequencies 0.43, 0.57, 0.65, and 0.35, respectively. While alleles C, T, A, and G frequencies were 0.28, 0.72, 0.32, and 0.68, respectively. CT and AG genotypes associated significantly (P < 0.05) with higher MP and LS, respectively. By studying the haplotypes of PRLR, C-A and T-A were associated with the highest and the lowest level of MP, respectively. For LS, T-A and C-G showed significant correlation with the highest and the lowest rate, respectively. Regarding IGF1 gene, two polymorphisms were detected; T74C at exon 4 which registered on NCBI as OM418860, and combined mutations as ins. G470, A531G, and T534C (PP genotype) at 5′ flanking region that registered as OM418859. For LEP, only one polymorphism was found in intron 2 (G281A) which submitted to NCBI as OM418855. All detected polymorphisms have shown to be involved in regulating the MP or LS as reproductive traits in goat.

Exploring the relationship between polymorphisms of leptin and IGF-1 genes with milk yield in indicine and taurine crossbred cows

Leptin an adipokine plays a significant role in several physiological processes and has been indicated as a candidate gene for marker-assisted selection for high-yielding cows. Insulin-like growth factor-1 (IGF-1) hormone plays an important physiological role in growth, development, metabolism, and lactation in bovines. It is believed to be one of the main mediators of energy balance effects on the reproductive performance of dairy cows after calving. The present investigation was carried out to identify the novel polymorphisms in exon 3 region of leptin and exon 3 partial intron 3 of IGF-1 genes and their association with the milk production performance in indicine and taurine crossbred (Karan Fries) cows. Blood samples were collected from 160 apparently healthy Karan Fries (KF) cows. Four SNPs (single-nucleotide polymorphisms) at positions rs29004508 (C > T), rs29004509 (C > T), rs29004510 (T > C), and rs29004511 (T > C) in leptin gene and two SNPs at positions rs133251968 (C > A) and rs137289661 (C > T) in IGF-1 gene were found in KF cows; however, rs29004509 (C > T) had a positive correlation (r = 0.376; P < 0.05) with milk yield. The genetic variants observed in exon 3 region of leptin gene and their association with milk yield traits revealed the importance of CT genotype, which had been useful for genetic improvement of KF cow for milk production traits and can also be utilized as a potential genetic marker to select appropriate animals.

Polymorphisms of IGF-IR gene and their association with economic traits in two indigenous Chinese dairy goat breeds

The insulin like growth factor 1 receptor (IGF-IR) plays an important role in regulating growth and development. To investigate the effects of IGF-IR polymorphisms on the economic traits of dairy goats, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods were used to screen single nucleotide polymorphisms (SNPs) within 9 IGF-IR fragments in Xinong Saanen dairy goat (XS, n = 268) and Guanzhong dairy goat (GZ, n = 440). Consequently, two SNPs, including NC_007319: g.26688 C>T (Leu 608 Leu) and NC_007319: g.28273 T>C within exon 9 and intron 10 were identified in R8 and R9 loci, respectively. At R8 locus, three genotypes were found, including CC, CT and TT, with genotypic frequencies of 0.11, 0.65 and, 0.24 respectively in XS goats, and 0.13, 0.78 and 0.09 in GZ goats; three genotypes which are C₁C₁, C₁T₁ and T₁T₁ were also found in R9 locus, with the genotypic frequencies of 0.48, 0.20 and 0.32 in XS goats, and 0.43, 0.22 and 0.35 in GZ goats, respectively. Based on χ² test, both XS and GZ populations were deviated from Hardy-Weinberg equilibrium at above two loci. The association analysis revealed that XS goats with CC genotype at R8 locus had heavier milk density than the CT ones (P < 0.05). At R9 locus, the body height of GZ goats with C₁C₁ and T₁T₁ genotypes was significantly higher than those with C₁T₁ genotype (P < 0.01 or P < 0.05). The individuals of GZ goat with C₁C₁ genotype had longer body length than those with T₁T₁ genotype (P < 0.05). The individuals of XS with T₁T₁ and C₁T₁ genotypes had higher body height than those with C₁C₁ genotype (P < 0.05). This study can provide theoretical and practical significances to improve the milk production traits and promote the growth and development in two Chinese indigenous dairy goat breeds.

Analysis of genetic diversity of Chinese dairy goats via microsatellite markers

In this study, 15 polymorphic microsatellite markers were used to analyze the genetic structure and phylogenetic relationships of 6 dairy goat breeds in China, including 4 native developed breeds and 2 introduced breeds. The results showed that a total of 172 alleles were detected in 347 samples of the dairy goat breeds included in this study. The mean number of effective alleles per locus was 4.92. Except for BMS0812, all of the remaining microsatellite loci were highly polymorphic (polymorphism information content [PIC] > 0.5). The analysis of genetic diversity parameters, including the number of effective alleles, PIC, and heterozygosity, revealed that the native developed dairy goat breeds in China harbored a rich genetic diversity. However, these breeds showed a low breeding degree and a high population intermix degree, with a certain degree of inbreeding and within-subpopulation inbreeding coefficient ( > 0). The analysis of population genetic differentiation and phylogenetic tree topologies showed a moderate state of genetic differentiation among subpopulations of native developed breed dairy goats in China (0.05 < gene fixation coefficient [] < 0.15). The native developed breeds shared a common ancestor, namely, the Saanen dairy goat, originating from Europe. The results showed that there was a close genetic relationship between Wendeng and Laoshan dairy goats while the Guanzhong dairy goat and the Xinong Saanen dairy goat were also found to have a close genetic relationship, which were both in agreement with the formation history and geographical distribution of the breeds. This study revealed that adopting genetic management strategies, such as expanding pedigree source and strengthening multi-trait selection, is useful in maintaining the genetic diversity of native developed breeds and improving the population uniformity of dairy goats.

Association of a Cac8I polymorphism in the IGF1 gene with growth traits in Indian goats

The Insulin-like Growth Factor 1 (IGF1) gene is a member of somatotropic axis and plays a key role in proliferation of cells, mitosis, myogenesis, meiosis, differentiation in foetal development and post natal growth. The objectives of this study were to verify the single nucleotide polymorphisms (SNPs) in IGF1 gene and their association with growth traits in two indigenous native goat genetic groups of Kerala, viz., Malabari and Attappady Black. A total of 277 goats were genotyped using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using the restriction enzyme Cac8I. One SNP, A224G was detected in the 5′ non-coding region of the IGF1 gene, and accordingly two genotypes were revealed, GG and AG. This SNP was significantly associated with growth traits in Attappady Black goats, which is maintained as meat breed in Kerala. Results from this study demonstrated higher performance of GG animals for growth traits. The association of IGF1 gene with these traits emphasizes the importance of caprine IGF1 as a candidate gene for growth traits in goat breeding.

Exploring the genetic signature of body size in Yucatan miniature pig

Since being domesticated about 10,000-12,000 years ago, domestic pigs (Sus scrofa domesticus) have been selected for traits of economic importance, in particular large body size. However, Yucatan miniature pigs have been selected for small body size to withstand high temperature environment and for laboratory use. This renders the Yucatan miniature pig a valuable model for understanding the evolution of body size. We investigate the genetic signature for selection of body size in the Yucatan miniature pig. Phylogenetic distance of Yucatan miniature pig was compared to other large swine breeds (Yorkshire, Landrace, Duroc and wild boar). By estimating the XP-EHH statistic using re-sequencing data derived from 70 pigs, we were able to unravel the signatures of selection of body size. We found that both selections at the level of organism, and at the cellular level have occurred. Selection at the higher levels include feed intake, regulation of body weight and increase in mass while selection at the molecular level includes cell cycle and cell proliferation. Positively selected genes probed by XP-EHH may provide insight into the docile character and innate immunity as well as body size of Yucatan miniature pig.

Polymorphism and association of growth hormone gene with growth traits in Sirohi and Barbari breeds of goat

AIM

The aim was to study the polymorphism of exon 2 and exon 3 of growth hormone (GH) gene, to test the polymorphic variants for Hardy-Weinberg equilibrium and to investigate association of these polymorphisms with chest girth and paunch girth in Sirohi and Barbari breeds of goat.

MATERIALS AND METHODS

A total of 80 kids involving forty each of Sirohi and Barbari breeds of goat were included in the study. A good quality genomic DNA isolated from the whole blood using standard protocol were used for polymerase chain reaction (PCR) amplification and products obtained on restriction digestion of amplicon with enzyme HaeIII were separated on 2% agarose gel, and documented in a gel doc system. The chest girth and paunch girth of kids at birth and weekly intervals up to 4 weeks of age and subsequently at 2 months, 3 months and 6 months of age were recorded. Allele frequency and genotype distribution of polymorphism were tested for Hardy-Weinberg equilibrium by program me Genepop package. Association between different genetic variants on chest girth and paunch girth were analyzed by least squares analysis employing suitable statistical model.

RESULTS

The PCR product of genomic DNA isolated from kids of Sirohi and Barbari breeds of goat on digestion with the restriction enzyme HaeIII revealed two genotypic variants viz., AB and BB. None of the two breeds was in Hardy-Weinberg equilibrium for these variants. The least squares analysis of variance revealed non-significant effect of GH genotype and breed × genotype interaction on chest girth and paunch girth from birth to 180 days of age. The effect of breed was highly significant (p<0.01) at all ages.

CONCLUSION

The present study showed that both the breeds were polymorphic at the exon 2 and exon 3 loci of GH gene under study with respect to HaeIII restriction endonuclease. None of the breeds was in Hardy-Weinberg equilibrium for this region of GH gene. In the present study, no significant association between GH genotype and chest girth and paunch girth could be established but comparatively higher chest girth and paunch girth were observed for AB genotype across the breeds.

Effects of CSN1S2 Genotypes on Economic Traits in Chinese Dairy Goats

The aim of this study was to investigate allele frequencies at the CSN1S2 locus in two Chinese dairy goat breeds and the effects of its variation on dairy goat economic traits. Seven hundred and eight goats from Xinong Saanen (XS, n = 268) and Guanzhong (GZ, N = 440) breeds were selected. The milk samples of 268 XS goats were collected during the middle of lactation, body size parameters (708 goats) and daily milk yield (202 goats) were registered. The RFLP (restriction fragment length polymorphism) and SSCP (single strand conformation polymorphism) were used to detect the polymorphisms in CSN1S2. The Hardy-Weinberg (HW) equilibrium and the associations between body size, milk yield and composition and the genotypes were calculated. The results revealed that only A and F CSN1S2 alleles were found in the two Chinese dairy goat breeds. Allelic frequencies of A and F were 0.795, 0.205 and 0.739, 0.261 in Xinong Saanen and Guanzhong population respectively. Xinong Saanen breed was in Hardy-Weinberg equilibrium, while Guanzhong breed deviated from Hardy-Weinberg equilibrium (p<0.05). The association of polymorphism with economic traits indicated that the goats with FF genotype have higher milk fat and total solid concentration than those with AA and AF genotypes (p<0.05).

Effects of nutrition level of concentrate-based diets on growth performance and carcass characteristics of Hainan black goats

This study assessed the effects of different nutrition levels of diets on growth performance and carcass characteristics of Hainan black goat. Twenty-four goats were divided into six diet treatments, which consisted of two levels of crude protein (CP; 15 and 17 %) and three levels of digestive energy (DE; 11.72, 12.55, and 13.39 MJ/kg). The results revealed that 17 % CP significantly (P < 0.05) increased ADG and improved FCR compared with 15 % CP. Therefore, the CP levels of diet affected growth performance. CP and DE levels in the diet had no significant effects (P > 0.05) on carcass characteristics of the goats. The mRNA expression levels of insulin-like growth factor 1 in muscle tissues increased with increasing CP and DE levels (P < 0.05).