A 5-bp mutation within MSTN/GDF8 gene was significantly associated with growth traits in Inner Mongolia White Cashmere goats

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.

Haplotype structure of MSTN, IGF1, and BMP2 genes in Tunisian goats (Capra hircus) and their association with morphometric traits

The aim of the present study was to evaluate variability and haplotype structure of twenty-eight single nucleotide polymorphisms (SNPs) at myostatin (MSTN), insulin-like growth factor 1 (IGF1), and bone morphogenetic protein 2 (BMP2) genes. Association between the polymorphic SNPs and morphometric traits was performed on a population of 263 Tunisian goats. The SNPs analyzed were all polymorphic (except one), and the three genes had different haplotype structures. Significant association of SNPs at MSTN with head length was highlighted in the Tunisian goats. The variability at IGF1 gene was associated with body length, ear length, tail length, and chest depth. For BMP2, significant association was revealed with chest depth. Significant association was also detected between linkage disequilibrium (LD) block 2 at IGF1 with body length. These findings might play a potential role in gene-assisted programs.

Goat SNX29: mRNA expression, InDel and CNV detection, and their associations with litter size

The sorting nexin 29 (SNX29) gene, a member of the SNX family, is associated with material transport and lipid metabolism. Previous studies have shown that lipid metabolism affects reproductive function in animals. Thus, we hypothesized there is a correlation between the SNX29 gene and reproductive trait. To date, studies on the relationship between the SNX29 gene and reproductive traits are limited. Therefore, the purpose of this study was to examine the polymorphism in the SNX29 gene and its correlation with litter size. Herein, the mRNA expression levels of SNX29 were assayed in various goat tissue. Surprisingly, we found that SNX29 was highly expressed in the corpus luteum, large and small follicles. This result led us to suggest that the SNX29 gene has a critical role in reproduction. We further detected potential polymorphisms in Shaanbei white cashmere (SBWC) goats, including insertion/deletion (InDel, n = 2,057) and copy number variation (CNV, n = 1,402), which were related to fertility. The 17 bp deletion (n = 1004) and the 20 bp deletion (n = 1,053) within the SNX29 gene were discovered to be significantly associated with litter size (P < 0.05), and individuals the ID genotype of P1-Del-17 bp and the DD genotype of P2-Del-20bp had larger litter size. Additionally, the four CNV loci had significant correlations with litter size (P < 0.01) in our detected population. In CNV5, individuals with the median genotype were superior compared to those with loss or gain genotype in term of litter size, and in other three CNVs showed better reproductive trait in the gain genotype. Briefly, these findings suggest that SNX29 could be used as a candidate gene for litter size in goat breeding through marker-assisted selection (MAS).

Identification of polymorphisms in the MSTN and ADRB3 genes associated with growth and ultrasound carcass traits in Kajli sheep

The aim of this investigation was to find single nucleotide polymorphisms (SNPs) in the myostatin (MSTN) and the beta-3 adrenergic receptor (ADRB3) genes associated with growth and ultrasound carcass traits in Kajli sheep. The five growth traits were birth weight (BWT-EBV), 120-day weight (120DWT-EBV), 180-day weight (180DWT-EBV), 270-day weight (270DWT-EBV), and 365-day weight (365DWT-EBV). The three ultrasound carcass traits were width (WLD) and depth of longissimus dorsi (DLD) and back fat thickness (BFT). The analysis of the MSTN sequence revealed one non-synonymous substitution (c.197T > A) in exon 1, one single nucleotide substitution (c.373 + 18G > T) in intron 1, and one synonymous substitution (c.861T > A) in exon 3. However, there were four single nucleotide synonymous substitutions (c.130C > T, c.294C > G, c.579G > T, and c.654C > G) in exon 1 of the ADRB3 gene. All the SNPs in the MSTN gene, except for c.373 + 18G > T, were in Hardy-Weinberg Equilibrium (HWE). Conversely, none of the SNPs found in ADRB3 were in HWE. Two of the MSTN SNPs (c.197T > A and c.373 + 18G > T) had significant associations with all evaluated growth and ultrasound carcass traits. The SNPs c.130C > T and c.294C > G in ADRB3 were significantly associated with 180DWT-EBV. Collectively, these findings indicate that several SNPs in the studied genes were significantly related to growth and carcass traits in Kajli sheep.

Effect of indel variants within the sorting nexin 29 (SNX29) gene on growth traits of goats

The sorting nexin 29 gene (SNX29) is a well-known regulator of myocyte differentiation and proliferation. In this work, two indels (17-bp and 21-bp) were identified in the goat SNX29 gene, and their effects on the growth traits of 1,759 Shaanbei white cashmere (SBWC) goats were analyzed. Both indels had three genotypes [homozygote wild type (II), heterozygote (ID), and homozygote mutation (DD)] and displayed medium genetic diversity (0.25 < polymorphism information content (PIC) < 0.50) in the population. The 17-bp indel was significantly associated with chest width (p = 0.009), body weight (p = 0.021), and chest depth (p = 0.032), with the II genotype dominant. The 21-bp indel was significantly associated with chest width (p = 0.001), chest depth (p = 4.8E-5), heart girth (p = 0.007), and hip width (p = 0.002). Because the two indels were in the upstream (17-bp) and intron (21-bp) regions of the SNX29 gene, transcription factor binding sites were predicted. The IRF5 and MYC could bind with the 17-bp indel and 21-bp indel sequences, respectively. This study indicates that SNX29 is a promising candidate gene that can be used to improve meat production in goat breeding.

Generation of Transgenic Cloned Buffalo Embryos Harboring the EGFP Gene in the Y Chromosome Using CRISPR/Cas9-Mediated Targeted Integration

Sex control technology is of great significance in the production of domestic animals, especially for rapidly breeding water buffalo (bubalus bubalis), which served as a research model in the present study. We have confirmed that a fluorescence protein integrated into the Y chromosome is fit for sexing pre-implantation embryos in the mouse. Firstly, we optimized the efficiency of targeted integration of exogenous gene encoding enhanced green fluorescent protein (eGFP) and mCherry in Neuro-2a cells, mouse embryonic stem cells, mouse embryonic cells (NIH3T3), buffalo fetal fibroblast (BFF) cells. The results showed that a homology arm length of 800 bp on both sides of the target is more efficient that 300 bp or 300 bp/800 bp. Homology-directed repair (HDR)-mediated knock-in in BFF cells was also significantly improved when cells were supplemented with pifithrin-μ, which is a small molecule that inhibits the binding of p53 to mitochondria. Three pulses at 250 V resulted in the most efficient electroporation in BFF cells and 1.5 μg/mL puromycin was found to be the optimal concentration for screening. Moreover, Y-Chr-eGFP transgenic BFF cells and cloned buffalo embryos were successfully generated using CRISPR/Cas9-mediated gene editing combined with the somatic cell nuclear transfer (SCNT) technique. At passage numbers 6–8, the growth rate and cell proliferation rate were significantly lower in Y-Chr-eGFP transgenic than in non-transgenic BFF cells; the expression levels of the methylation-related genes DNMT1 and DNMT3a were similar; however, the expression levels of the acetylation-related genes HDAC1, HDAC2, and HDAC3 were significantly higher (p < 0.05) in Y-Chr-eGFP transgenic BFF cells compared with non-transgenic cells. Y-Chr-eGFP transgenic BFFs were used as donors for SCNT, the results showed that eGFP reporter is suitable for the visualization of the sex of embryos. The blastocyst rates of cloned buffalo embryos were similar; however, the cleavage rates of transgenic cloned embryos were significantly lower compared with control. In summary, we optimized the protocol for generating transgenic BFF cells and successfully generated Y-Chr-eGFP transgenic embryos using these cells as donors.