Determination of the novel genetic variants of goat STAT5A gene and their effects on body measurement traits in two Chinese native breeds

A novel 22-bp InDel within FGF7 gene is significantly associated with growth traits in goat

Fibroblast growth factor 7 (FGF7) is involved in lipid metabolism, which is considered as a candidate gene with close relation with muscle development by eGWAs and RNA-Seq analyses. To date, limited research has been conducted on the relationship between FGF7 gene and growth traits. The main objective of this work was to further investigate the association between novel InDel within FGF7 gene and growth traits in goat. Herein, FGF7 mRNA expression levels were investigated in various Fuqing goat tissues. We found that FGF7 gene was expressed in six adult goat tissues with the highest mRNA levels in adipose tissue. This result suggested that FGF7 gene might play a critical role in fat deposition. We also detected potential polymorphisms in Fuqing, Nubian and Jianyang Daer breeds. A 22-bp InDel polymorphism in FGF7 gene was detected in 396 goats and the three genotypes were designated as II, ID, and DD. Correlation analysis revealed that InDel polymorphism was significantly associated with growth traits (P < 0.05). Goats with genotypes ID and/or II had superior growth traits compared to those with genotype DD. In summary, our findings suggested that the 22-bp InDel within FGF7 gene could act as a molecular marker to improve the growth traits of goats in breeding programs.

Association analysis of indels in the VISFATIN gene with five cattle breeds and their growth traits

VISFATIN is an adipose cytokine that has been proved to correlate with growth and development traits. In a previous study from our lab, two insertion/deletions (indels; including a 35-bp insertion at its intron 4 and a 6-bp deletion in intron 5) were identified within the VISFATIN gene. To validate these indels and evaluate their association with growth traits in Chinese cattle, a total of 413 samples from four Chinese indigenous breeds and 217 samples from Chinese breeds were detected. Three genotypes (WW, WI and II) at intron 4 were detected based on the 35-bp insertion (allele I) or deletion (allele W) and showed moderate polymorphism in all samples. Two genotypes (WW and WD) at intron 5 were detected based on the 6-bp deletion (allele D) or insertion (allele W) in Xianan (XN) cattle and Jinnan (JN) cattle population but showed poor polymorphisms. Association analysis illustrated that the indel at intron 4 is significantly associated with chest girth, rump length and body weight in Ji'an (JA) cattle and the indel at intron 5 can cause a significant difference in rump length in JN cattle. To our knowledge, it is the first time it has been shown that indels within the VISFATIN gene are associated with growth traits in the two Chinese indigenous cattle breeds. These findings suggest that the VISFATIN gene can be used as a molecular marker for JN and JA cattle breeding.

Genetic polymorphisms within the ETAA1 gene associated with growth traits in Chinese sheep breeds

Ewing tumor-associated antigen 1 (ETAA1) is an important candidate gene for fat deposition in sheep. This study aimed to investigate the indel variations in the ETAA1 gene and their associations with growth traits in the 1619 sheep. The polymorphism information content of this indel ranged from 0.308 to 0.375, with medium genetic diversity (0.25 ≤ polymorphism information content ≤ 0.5). The correlation analysis showed that an 8-bp insertion within the ETAA1 gene was significantly associated with growth traits in Luxi Blackhead sheep (LXBH), Lanzhou fat-tailed sheep, Hu sheep, Tong sheep, and Tan sheep (p < 0.05). Furthermore, the ETAA1 gene was significantly associated with several growth traits (p < 0.01), such as chest width and paunch girth of LXBH, Tong, and Tan rams. It was significantly related to the body morphometric traits of LXBH, Lanzhou fat-tailed sheep, Hu, Tong, and Tan ewes. In conclusion, the detected 8-bp indel within the ETAA1 gene was confirmed in sheep, significantly affecting the growth traits, and might be a potential DNA marker for the selection of high-quality individuals in marker-assisted selection for sheep breeding.

Detecting novel Indel variants within the GHR gene and their associations with growth traits in Luxi Blackhead sheep

The growth hormone is important in the regulation of metabolism and energy homeostasis and acts through a growth hormone receptor (GHR). In this work, genetic variations within the ovine GHR gene were identified and tested for associations with body morphometric traits in Chinese Luxi Blackhead (LXBH) sheep. Novel deletion loci in the LXBH GHR gene included P2-del-23 bp and P8-del-23 bp indel variants. The polymorphic information content (PIC) was 0.329 in P2-del-23 bp and 0.257 in P8-del-23 bp. Moreover, both indel polymorphisms were not at Hardy-Weinberg equilibrium (p < 0.05) in the LXBH population. Statistical analyses revealed that the P2-del-23 bp and P8-del-23 bp indels were significantly associated (p < 0.05) with several growth traits in rams and ewes, including body weight, body height, chest depth, chest width, chest circumference, cannon circumference, paunch girth and hip width. Among the tested sheep, the body traits of those with genotype DD were superior to those with II and ID genotypes, suggesting that the 'D' allele was responsible for the positive effects on growth traits. Thus, these results indicate that the P2-del-23 bp and P8-del-23 bp indel sites and the DD genotype can be useful in marker-assisted selection in sheep.

Goat DNMT3B: An indel mutation detection, association analysis with litter size and mRNA expression in gonads

DNA methyltransferase 3β (DNMT3B) is a gene encoding a de novo methylation enzyme that is required for DNA methylation during mammalian embryo development. Previous genome-wide association analysis suggested DNMT3B is a candidate gene for goat fertility, but there is no study on the effect of DNMT3B on litter size in goat. The aim of this study was to identify possible insertion/deletion (indel) mutations associated with litter size. Seven putative indels were designed to study their association with litter size, but just one 11-bp insertion variant of intron 22 (the last intron) was found in healthy female Shaanbei white cashmere goats (SBWC goats) (n = 1534). Statistical analysis showed that the 11-bp insertion was related to the first-born litter size (P < 0.01) and the goats with the deletion/deletion genotype had a higher average first-born litter size (P < 0.01). In addition, the expression profile of the DNMT3B mRNA in goat was detected, which revealed significant differences in DNMT3B mRNA expression in the gonads. Additionally, the results of western blotting revealed that the ovaries of mothers of multi-lamb (MML) had a higher level of DNMT3B protein than the ovaries of mothers of single-lamb (MSL). Furthermore, the mRNA of DNMT3B was widely expressed in male goats. Differences in mRNA expression levels were observed in the ovaries of MSL and MML. These findings indicated that the 11-bp indel in DNMT3B was significantly associated with first-born litter size, which can be used for marker-assisted selection (MAS) of goats for breeding.

A novel 23 bp indel mutation in PRL gene is associated with growth traits in Luxi Blackhead sheep

Prolactin is a highly versatile pituitary hormone with multiple biological functions. PRL expression is regulated by POU1F1 and the prophet of POU1F1 (PROP1). The aim of this study was to investigate the indel variations in ovine PRL and the directly related (PROP1 and POU1F1) genes, and their associations with growth traits in Luxi Blackhead (LXBH) sheep. A monomorphism in PROP1 and POU1F1 genes, and one novel 23-bp insertion mutation in the PRL gene, were identified in LXBH sheep. The 23 bp insertion mutation within PRL gene was significantly associated with several body measurements (e.g., body weight, body height) in sheep of different ages (p < 0.05). Ram lambs (p = 0.036) of genotype insertion/insertion (II) had significantly higher body weights. Weaners (p = 0.018) of genotypes insertion/insertion (II) and insertion/deletion (ID) also had significantly higher body weights compared with male sheep of deletion/deletion (DD) genotype. Moreover, among ewe lambs, individuals of genotype insertion/insertion (II) had a higher paunch girth compared to those with other genotypes (p = 0.044). These findings indicate that a 23 bp indel variant of the ovine PRL gene is correlated with body measurements in LXBH sheep. The findings have potential utility for sheep breeding programs based on marker-assisted selection.

Screening of Deletion Variants within the Goat PRDM6 Gene and Its Effects on Growth Traits

Simple Summary

Genome-wide association studies found that the PR/SET Domain 6 (PRDM6) gene mutation was associated with bone development, bone density, and body mass index. This study found a 12 bp deletion variation within the PRDM6 gene in Shaanbei white cashmere goats in a large sample size (n = 1044). This variation polymorphism was associated with multiple goat growth traits in the yearling period, including heart girth (p = 0.027), cannon circumference (p = 0.008), chest depth (p = 2.10 × 10⁻⁵), chest width (p = 0.004), body height (p = 0.032), body length (p = 0.044), and hip-width (p = 0.014). The effects of the 12 bp variation were found to make no difference on adult goat growth traits. Taken together, these results demonstrate that the 12 bp deletion variant plays an important role in the early growth and development of goats and could be considered as a useful and effective molecular marker for goat breeding selection in the growth stage.

Abstract

By genome-wide association studies, the PRDM6 gene has been shown to affect multiple, apparently unrelated inherited traits, including bone density and body mass index. Therefore, it is considered a potentially pleiotropic gene. In this study, we identified a 12 bp deletion variant (NC_030814.1:rs651603667, g: 79985625-79985636delTTGACTGATCCA) within the PRDM6 gene in a large sample (SBWC goats; n = 1044). All goat samples were collected in Shaanxi province in July 2018. The frequency of the wt allele was higher than the frequency of the del allele, and this mutation polymorphism confirmed to be consistent with the Hardy–Weinberg equilibrium (p > 0.05). Further results showed that in a group of goats in the yearling period (18 months old, n = 567), this deletion variant of the PRDM6 gene was associated with heart girth (p = 0.027), cannon circumference (p = 0.008), chest depth (p = 2.10 × 10⁻⁵), chest width (p = 0.004), body height (p = 0.032), body length (p = 0.044) and hip-width (p = 0.014). For adult SBWC goats (36 months old, n = 477), the effects of the 12 bp variation on growth-related traits were found to make no difference. These findings show that the 12 bp deletion within the goat PRDM6 gene plays an important role in the early growth and development of goats. Using the 12 bp mutation, breeders can quickly and effectively select excellent individual goats at an early stage.

A novel duplicated insertion/deletion (InDel) of the CPT1a gene and its effects on growth traits in goat

Carnitine palmitoyltransferase 1a (CPT1a) is a rate-limited enzyme in the mitochondrial fatty acid β-oxidation pathway. It acts as a bridge between PPARα and the fatty acid oxidation pathways and is closely related to ruminant growth and development. In this study, one 12 bp InDel polymorphism of the CPT1a gene was identified in 700 goats, and we designated these three genotypes II, ID, and DD. Association analysis showed that the InDel polymorphism was closely associated with trunk index (p = 0.008) and body length index (p = 0.034) in Hainan black goats, and body length (p = 0.010), chest circumference (p = 0.004), chest depth (p = 0.029), and huckle bone width (p = 0.002) in Nubian goats, as well as the chest circumference (p = 0.016) in the Fuqing goat breed. In both kids and adult goats, qRT-PCR results showed that the CPT1a gene was expressed in all tissues, showing the highest mRNA levels in the liver, lung, spleen, and kidney, followed by the adipose tissue and brain. This indicates an association between the InDel of the CPT1a gene and growth traits in selected goat breeds, which may facilitate marker-assisted selection in goat genetics and breeding.

Two Insertion/Deletion Variants within SPAG17 Gene Are Associated with Goat Body Measurement Traits

Simple Summary

Sperm-associated antigen 17 (SPAG17) is a reproduction and skeletal development related gene. This study aimed to identify crucial insertion-deletion (indel) variations, which influence the body measurement traits of goats. Two intronic indels (14 bp and 17 bp indels) were identified by sequencing. In Shaanbei white cashmere goat (SBWC), the different genotypes of the 14 bp indel were markedly associated with goat body height, chest width, body length, and chest depth. The genotypes of the 17 bp indel were significantly associated with body height and chest width. The different combined genotypes were significantly associated with body height and chest width of SBWC and ten traits of Hainan black goat. These results suggested that the 14 and 17 bp indels within SPAG17 can be used in goat growth related traits marker-assisted selection breeding, especially body height.

Abstract

Sperm-associated antigen 17 (SPAG17) gene encodes a multifunctional cytoplasmic protein, which influences not only reproduction but also skeletal development related body measurement traits, especially body height. Thus, this study aimed to identify crucial insertion-deletion (indel) variations, which influence the body measurement traits of goats in large goat populations (n = 1725). As a result, two intronic indels (14 bp and 17 bp indel) were identified by sequencing. For the two indel loci, the distributions of genotypes and alleles were significantly different between the Shaanbei white cashmere goat (SBWC) and the Hainan black goat (HNBG). In SBWC goats, the different genotypes of the 14 bp indel were markedly associated with goat body height, chest width, body length and chest depth. The genotypes of the 17 bp indel were significantly related to body height and chest width. At the two loci, for all seven analyzed traits of SBWC goat, the growth data of DD homozygotes were the worst, which means that the 14 bp insertion and the 17 bp deletion were beneficial and detrimental variations, respectively. Moreover, the combined genotypes were significantly related to body height and chest width of SBWC goats and ten traits of HNBG. These results suggested that the 14 and 17 bp indels within SPAG17 can be used in goat growth related traits marker-assisted selection breeding, especially body height.

Effects of genetic variations within goat PITX2 gene on growth traits and mRNA expression

Paired-like homeodomain 2 (PITX2), a key gene in hypothalamic-pituitary-adrena axis, influences animal growth and development. The objective of this study was to identify the association of the functional genetic variations within goat PITX2 gene with growth traits and mRNA expression levels. According to the reported single nucleotide polymorphisms (SNPs) information in Guanzhong dairy goat (GZDG), we identified genotypes of the known SNPs in Hainan black goat (HNBG). Association analysis uncovered that the SNPs of AC_000163: g.18117T > C, g.18161C > G and g.18353T > C loci were significantly associated with several growth traits (e.g., body height and body length) in HNBG and GZDG breeds. According to the quantitative real-time PCR assay, β-Actin and ribosomal protein L19 (RPL19) were the most stable expressed housekeeping genes in heart and skeletal muscle, respectively; meanwhile, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was the most stable expressed housekeeping gene in the other tissues. Based on the best housekeeping gene of varied tissues, we found the different genotypes of above loci were significantly associated with PITX2 mRNA expression in heart, muscle and small intestine. Briefly, the genetic variants of goat PITX2 associating with mRNA expression affected growth traits significantly, which would benefit for goat breeding in the future.

Two strongly linked single nucleotide polymorphisms (Q320P and V397I) in GDF9 gene are associated with litter size in cashmere goats

Growth differentiation factor 9 (GDF9) gene is an effective intra-ovarian regulator; it plays a crucial role in early folliculogenesis in female mammals. The non synonymous mutations: g.3905A > C (also known as p.Gln320Pro/Q320P) and g.4135G > A (also know as p.Val397Ile/V397I), are two well-known and controversial single nucleotide polymorphisms (SNPs) within GDF9 gene in goats with different prolificacy, and so far, there were no studies on linkage between Q320P and V397I. Therefore, the aim of this work was to study whether Q320P and V397I mutations have a significant effect on litter size, in Shaanbei white cashmere goats (SBWC, n = 1511), and to explore the specific relationship between these two SNPs. The results showed that both of Q320P and V397I mutations exhibited three genotypes; the minor allele frequencies (MAF) of the SNPs were 0.286 and 0.477, respectively; and these two SNPs were in strong linkage disequilibrium (D' = 0.976, r² = 0.348) in the studied goats. Moreover, association analyses revealed that Q320P was significantly associated with the first-born litter size in goats irrespective of the sample size (n = 1511; P = 0.008), while V397I significantly affected litter size until the sample size crossed 1300 (P = 0.015). Meanwhile, the diplotypes PP-II and QP-VI were observed to have a superior effect on litter size (P = 3.78 × 10^-5) to that of the haplotypes (P = 1.12 × 10^-7). Thus, the findings led us to assume that Q320P mutation was the major SNP affecting goat litter size. These findings can provide useful DNA markers for selecting superior individuals in marker-assisted selection (MAS) for breeding in relation to fecundity in goats.

Evaluation of novel SNPs and haplotypes within the <i>ATBF1</i> gene and their effects on economically important production traits in cattle

Abstract. AT motif binding factor 1 (ATBF1) gene can promote the expression level of the growth hormone 1 (GH1) gene by binding to the enhancers of the POU1F1 and PROP1 genes; thus, it affects the growth and development of livestock. Considering that the ATBF1 gene also has a close relationship with the Janus kinase–signal transductor and activator of transcription (JAK–STAT) pathway, the objective of this work was to identify novel single-nucleotide polymorphism (SNP) variations and their association with growth traits in native Chinese cattle breeds. Five novel SNPs within the ATBF1 gene were found in 644 Qinchuan and Jinnan cattle for first time using 25 pairs of screening and genotyping primers. The five novel SNPs were named as AC_000175:g.140344C>G (SNP1), g.146573T>C (SNP2), g.205468C>T (SNP3), g.205575A>G (SNP4) and g.297690C<T (SNP5). Among them, SNP1 and SNP2 were synonymous coding SNPs, while SNP5 was a missense coding SNP, and the other SNPs were intronic. Haplotype analysis found 18 haplotypes in the two breeds, and three and five closely linked loci were revealed in Qinchuan and Jinnan breeds, respectively. Association analysis revealed that SNP1 was significantly associated with the height across the hip in Qinchuan cattle. SNP2 was found to be significantly related to chest circumference and body side length traits in Jinnan cattle. SNP3 was found to have significant associations with four growth traits in Qinchuan cattle. Moreover, the different combined genotypes, SNP1–SNP3, SNP1–SNP4 and SNP2–SNP5 were significantly associated with the growth traits in cattle. These findings indicated that the bovine ATBF1 gene had marked effects on growth traits, and the growth-trait-related loci can be used as DNA markers for maker-assisted selection (MAS) breeding programs in cattle.

A novel synonymous SNP (A47A) of the <i>TMEM95</i> gene is significantly associated with the reproductive traits related to testis in male piglets

Abstract. Transmembrane protein 95 (TMEM95) is located on the acrosomal membrane of the sperm head involved in the acrosome reaction; thus, it is regarded as affecting spermatogenesis and reproduction traits. The aim of this study was to explore the novel single nucleotide polymorphisms (SNPs) within the pig TMEM95 gene as well as to evaluate their associations with the testicular sizes in male Landrace (LD) and Large White (LW) breeds. After pool sequencing and bioinformatics analysis, only one novel coding SNP was found in exon 1, namely NC_010454.3: g.341T > C, resulting in a synonymous mutation (A47A). This SNP could be genotyped using the StuI polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) assay. The minor allelic frequencies (MAFs) were 0.259 and 0.480 in the LD and LW breeds. Their polymorphism information content (PIC) values were 0.310 and 0.375. The LW population was at the Hardy–Weinberg equilibrium (HWE) (p > 0.05), whereas the LD population was not (p < 0.05). Association analyses demonstrated that a significant relationship was found between this A47A polymorphism and testis weight at 40 days of age in the LW population (p  =  0.047), and the heterozygote individuals showed lower testis weight than those with other genotypes. Moreover, this SNP was significantly associated with three testis measurement traits at 15 days of age in the LW population (p < 0.05); the individuals with genotypes TT and TC showed consistently superior testis measurement traits than those with genotype CC. These findings demonstrate that the A47A polymorphism had a significant effect on testis measurement traits, suggesting that the TMEM95 gene could be a candidate gene associated with reproductive traits. These results could contribute to breeding and genetics programs in the pig industry via DNA marker-assisted selection (MAS).

Identification of a novel 12-bp insertion/deletion (indel) of iPS-related Oct4 gene and its association with reproductive traits in male piglets

As a key factor of cellular reprogramming, Oct4 is one of vital transcription factors for induced pluripotent stem cells (iPSCs). Loss of its function or deletion causes apoptosis in primordial germ cells (PGCs), which affect reproductive traits in mammals. In this study, a novel 12-bp insertion/deletion (indel) polymorphism (NC_010449:g.2759-2760insGGTTTTTGTCTA) within the Oct4 gene was identified in 442 pigs of Large White (LW) and Landrace (LD) breeds, showing three genotypes designated as II, ID, and DD. The frequencies of allele "I" in LW and LD pigs were 0.587 and 0.648, respectively. The male piglets with homozygous II or DD genotypes of Oct4 gene exhibited better reproductive traits than those with heterozygous ID genotype. Moreover, there were two significant associations between this 12-bp indel polymorphism and testis long circumference (TLC) (P=0.005) and testis short girth (TSG) (P=0.003) as well as 15-day testis weight (TW) (P=0.013) in the LW male piglets. These findings suggest that the 12-bp indel polymorphism of the Oct4 gene might be a potential DNA marker for selecting preferred individuals in relation to reproductive traits in pig marker-assisted selection (MAS) breeding, which could contribute to the breeding and genetics in male piglets.

The 10 bp duplication insertion/deletion in the promoter region within paired box 7 gene is associated with growth traits in cattle

Abstract. Paired box 7 (Pax7) gene, a member of the paired box gene family, plays a critical role in animal growth and muscle development, especially in cell proliferation and self-renewal. The aim of this study was to detect the 10 base pair (bp) duplication insertion/deletion (indel) in the promoter region within the bovine Pax7 gene as well as its association with growth traits. Herein, a total of 718 individuals from five Chinese cattle breeds were sampled and detected. The 10 bp duplication indel was found in these cattle breeds and there were three genotypes: II (insertion/insertion), ID (insertion/deletion), and DD (deletion/deletion). Moreover, this indel was significantly associated with the body weight in Xianan cattle (P = 0.006), the body height in Jinjiang cattle (P = 0.046), and the hip width in Pi'nan cattle (P = 0.020). Consistently, the individuals with II genotype showed better phenotypic traits than those with the other genotypes in these five breeds. These findings suggest that the 10 bp duplication indel within the bovine Pax7 gene could be considered as an effective DNA molecular marker that provides valuable theoretical basis for marker-assisted selection (MAS) in beef cattle in the future.