Boosting CO2 Photoreduction to Formate or CO with High Selectivity over a Covalent Organic Framework Covalently Anchored on Graphene Oxide.

Covalent organic frameworks (COFs) have been widely studied in photocatalytic CO2 reduction reaction (CO2 RR). However, pristine COFs usually exhibit low catalytic efficiency owing to the fast recombination of photogenerated electrons and holes. In this study, we fabricated a stable COF-based composite (GO-COF-366-Co) by covalently anchoring COF-366-Co on the surface of graphene oxide (GO) for the photocatalytic CO2 reduction. Interestingly, in absolute acetonitrile (CH3 CN), GO-COF-366-Co shows a high selectivity of 94.4 % for the photoreduction of CO2 to formate, with a formate yield of 15.8 mmol/g, which is approximately four times higher than that using the pristine COF-366-Co. By contrast, in CH3 CN/H2 O (v : v=4 : 1), the main product for the photocatalytic CO2 reduction over GO-COF-366-Co is CO (96.1 %), with a CO yield as high as 52.2 mmol/g, which is also approximately four times higher than that using the pristine COF-366-Co. Photoelectrochemical experiments demonstrate the covalent bonding of COF-366-Co and GO to form the GO-COF-366-Co composite facilitates charge separation and transfer significantly, thereby accounting for the enhanced catalytic activity. In addition, theoretical calculations and in situ Fourier transform infrared spectroscopy reveal H2 O can stabilize the *COOH intermediate to further form a *CO intermediate via O-H(aq)⋅⋅⋅O(*COOH) hydrogen bonding, thus explaining the regulated photocatalytic performance.

Mechanochromic and Selective Vapochromic Solid-State Luminescence of a Dinuclear Cuprous Complex.

The unraveling of the stimuli-responsive mechanism is crucial to the design and precise synthesis of stimuli-responsive luminescent materials. We report herein the mechanochromic and selective vapochromic solid-state luminescence properties of a new bimetallic cuprous complex [{Cu(bpmtzH)}2(µ-dppm)2](ClO4)2 (1), and the corresponding response mechanisms are elucidated by investigating its two different solvated polymorphs 1·2CH2Cl2 (1-g) and 1·2CHCl3 (1-c). Green-emissive 1-g and cyan-emissive 1-c can be interconverted upon alternate exposure to CHCl3 and CH2Cl2 vapors, which is principally attributable to a combined alteration of both intermolecular NHbpmtzH···OClO3- hydrogen bonds and intramolecular "triazolyl/phenyl" π···π interactions induced by different solvents. Solid-state luminescence mechanochromism present in 1-g and 1-c is mainly ascribed to the grinding-induced breakage of the NHbpmtzH···OClO3- hydrogen bonds. It is suggested that intramolecular π···π-triazolyl/phenyl interactions are affected by different solvents but not by grinding. The results provide new insights into the design and precise synthesis of multi-stimuli-responsive luminescent materials by the comprehensive use of intermolecular hydrogen bonds and intramolecular π···π interactions.

Water-Etched Approach to Hierarchically Porous Metal-Organic Frameworks with High Stability.

The development of hierarchically porous metal-organic frameworks (MOFs) with high stability is desirable to expand their applications but remains challenging. Herein, an anionic sodalite-type microporous MOF (Yb-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was synthesized, which shows outstanding catalytic activities for the cycloaddition of CO2 into cyclic carbonates. Moreover, the microporous Yb-TTCA can be transformed into a hierarchical micro- and mesoporous Yb-TTCA by water treatment with the mesopore sizes of 2 to 12 nm. The hierarchically porous Yb-TTCA (HP-Yb-TTCA) not only exhibits a high thermal stability up to 500 °C but also shows a high chemical stability in aqueous solutions with pH values ranging from 2 to 12. In addition, the HP-Yb-TTCA displays enhanced performance for the removal of organic dyes in comparison with microporous Yb-TTCA. This work provides a facile way to construct hierarchically porous MOF materials.

Diarrhea in suckling lambs is associated with changes in gut microbiota, serum immunological and biochemical parameters in an intensive production system.

The incidence of diarrhea in lambs is frequent in large-scale sheep farms, which greatly impacts the growth and health of lambs. The aim of this study was to assess the changes in serum biochemical and immunological parameters and gut microbiome composition in suckling lambs suffering from diarrhea or not, reared on an intensive commercial farm. We found a reduced diversity of intestinal bacteria in suckling lambs suffering from diarrhea. Firmicutes and Bacteroidetes were the dominant flora in both groups of lambs, while the Bacteroidetes decreased in diarrheic lambs, no changes were reported in Firmicutes. Compared with healthy lambs, the proportion of aerobic bacteria, facultative anaerobic bacteria, and stress tolerant bacteria increased in lambs suffering from diarrhea, while that of anaerobic bacteria and potentially pathogenic bacteria decreased slightly. In addition, the contents of total cholesterol, immunoglobulins (Ig) G, and IgM in the serum of lambs suffering from diarrhea were lower than those of healthy lambs. This study explored the association between diarrhea occurrence, intestinal microbial community structure, and metabolic and immunological status in Hu lambs.

Detection of small sequence variations within the goat GHR gene and its effects on growth traits.

Growth hormone receptor (GHR) gene is considered to be an important candidate gene in growth traits. Therefore, the purpose of this study was to detect whether there were potential indel variations in the GHR gene that were related to the growth traits of the Shaanbei white cashmere goats (SBWC). In this study, genomic DNA from 931 healthy SBWC individuals were used to verify the relationship between the indel of the GHR gene and growth traits. Two indel variants, P49-bp indel in intron 1 and P1410-bp indel in 3'-UTR, were confirmed. Association analyses demonstrated that these two indel polymorphism loci were associated with the chest circumference and chest width of SBWC. Additionally, for the P49-bp and P1410-bp indel loci, the ID and II genotypes were dominant genotypes, respectively. Moreover, the genotypic distributions of these two indel loci in SBWC were significantly different from those in three other Chinese indigenous goat breeds (HNBG, GZDG and IMWC) (p < 0.05). Taken together, two indel loci (P49-bp indel and P1410-bp indel) both significantly affected the growth traits of goats. This illustrated that these two indel loci might be the potential DNA marker for use in improving the selection and breeding of goats.

A Single-cell Transcriptome Atlas of Cashmere Goat Hair Follicle Morphogenesis.

Cashmere, also known as soft gold, is produced from the secondary hair follicles (SHFs) of cashmere goats. The number of SHFs determines the yield and quality of cashmere; therefore, it is of interest to investigate the transcriptional profiles present during cashmere goat hair follicle development. However, mechanisms underlying this development process remain largely unexplored, and studies regarding hair follicle development mostly use a murine research model. In this study, to provide a comprehensive understanding of cellular heterogeneity and cell fate decisions, single-cell RNA sequencing was performed on 19,705 single cells of the dorsal skin from cashmere goat fetuses at induction (embryonic day 60; E60), organogenesis (E90), and cytodifferentiation (E120) stages. For the first time, unsupervised clustering analysis identified 16 cell clusters, and their corresponding cell types were also characterized. Based on lineage inference, a detailed molecular landscape was revealed along the dermal and epidermal cell lineage developmental pathways. Notably, our current data also confirmed the heterogeneity of dermal papillae from different hair follicle types, which was further validated by immunofluorescence analysis. The current study identifies different biomarkers during cashmere goat hair follicle development and has implications for cashmere goat breeding in the future.

Incorporation of Chromophores into Metal-Organic Frameworks for Boosting CO2 Conversion.

The exploitation of highly stable and active catalysts for the conversion of CO2 into valuable fuels is desirable but is a great challenge. Herein, we report that the incorporation of chromophores into metal-organic frameworks (MOFs) could afford robust catalysts for efficient CO2 conversion. Specifically, a porous Nd(III) MOF (Nd-TTCA; TTCA3- = triphenylene-2,6,10-tricarboxylate) was constructed by incorporating one-dimensional Nd(CO2)n chains and TTCA3- ligands, which exhibits a very high stability, retaining its framework not only in the air at 300 °C for 2 h but also in boiling aqueous solutions at pH 1-12 for 7 days. More importantly, Nd-TTCA has achieved a 5-fold improvement in photocatalytic activity for reducing CO2 to HCOOH and a 10-fold improvement in catalytic activity for the cycloaddition of CO2 into cyclic carbonate in comparison to those of H3TTCA itself. This work gives a new strategy to design efficient artificial crystalline catalysts for CO2 conversion.

Deletion mutation within the goat PPP3CA gene identified by GWAS significantly affects litter size.

The protein phosphatase 3 catalytic subunit α (PPP3CA) gene is a high reproduction traits candidate gene for goats as revealed by a genome-wide association study. The aim of this work was to explore the genetic variations of the goat PPP3CA as well as to evaluate the genetic effects on litter size. Three novel insertions/deletions (indels) within the goat PPP3CA were found and their minor allelic frequencies (MAF) were 0.105, 0.066, and 0.042, respectively. The results showed that only the 20bp indel polymorphism was significantly associated with litter size in Shaanbei white cashmere goats (P<0.05) and individuals with deletion/deletion (DD) genotypes demonstrated the junior phenotypes when compared with those with other genotypes. These findings suggested that the 20bp indel is a potential DNA marker for selecting superior individuals in marker-assisted selection for breeding concerning fecundity in goats.

Integrative Analysis of Methylome and Transcriptome Reveals the Regulatory Mechanisms of Hair Follicle Morphogenesis in Cashmere Goat.

Studies in humans and mice have revealed that hair follicle morphogenesis relies on tightly coordinated ectodermal-mesodermal interactions, involving multiple signals and regulatory factors. DNA methylation and long non-coding RNA (lncRNA) play a critical role in early embryonic skin development by controlling gene expression. Acting as an indirect regulator, lncRNA could recruit DNA methyltransferases to specific genomic sites to methylate DNA. However, the molecular regulation mechanisms underlying hair follicle morphogenesis is unclear in cashmere goat. In this study, RNA-seq and whole-genome bisulfite sequencing (WGBS) in embryonic day 65 (E 65) and E 120 skin tissues of cashmere goat were used to reveal this complex regulatory process. The RNA-seq, qRT-PCR, and immunohistochemistry results showed that Wnt signaling played an important role in both hair follicle induction and differentiation stage; transcriptional factors (TFs), including HOXC13, SOX9, SOX21, JUNB, LHX2, VDR, and GATA3, participated in hair follicle differentiation via specific expression at E 120. Subsequently, the combination of WGBS and RNA-seq analysis showed that the expression of some hair follicle differentiation genes and TF genes were negatively correlated with the DNA methylation level generally. A portion of hair follicle differentiation genes were methylated and repressed in the hair follicle induction stage but were subsequently demethylated and expressed during the hair follicle differentiation stage, suggesting that DNA methylation plays an important role in hair morphogenesis by regulating associated gene expression. Furthermore, 45 upregulated and 147 downregulated lncRNAs in E 120 compared with E 65 were identified by lncRNA mapping, and then the potential differentially expressed lncRNAs associated with DNA methylation on the target gene were revealed. In conclusion, critical signals and genes were revealed during hair follicle morphogenesis in the cashmere goat. In this process, DNA methylation was lower in the hair follicle differentiation compared with the hair follicle induction stage and may play an important role in hair morphogenesis by regulating associated gene expression. Furthermore, potential lncRNAs associated with DNA methylation on target genes were delineated. This study enriches the regulatory network and molecular mechanisms on hair morphogenesis.

Genetic effects of DSCAML1 identified in genome-wide association study revealing strong associations with litter size and semen quality in goat (Capra hircus).

The down syndrome cell adhesion molecule like 1 (DSCAML1), is associated with the development of the nervous system and neurologic diseases. Previous Genome-wide association studies have shown that it is associated with sperm morphology, suggesting it has a critical role in fecundity. In this study, expression profiles of goat DSCAML1 mRNA were analyzed. The results showed that its expression in the testis differ significantly between the mitotic stage and meiotic stage. Three insertion/deletion (indel) variants of goat DSCAML1 were determined in the Shaanbei White Cashmere Goat (SWCG, n = 2162). Based on the association analysis, two indels (P2-16bp, P14-15bp) were significantly related to sperm quality (sperm motility and sperm density) in male goat and three loci were markedly related to the first-birth litter size in female goat (P = 4.0 × 10-6; P = 1.0 × 10-6; P = 4.7 × 10-2). In male goats, the different genotypes of P2-16bp and P14-15bp revealed a noticeable effect on the expression of DSCAML1. Moreover, the effects observed in the first-birth litter followed a similar trend, which may provide the basis for further research of DSCAML1 gene function and marker assisted selection (MAS) programs to improve reproductive traits.

An 11-bp Indel Polymorphism within the CSN1S1 Gene Is Associated with Milk Performance and Body Measurement Traits in Chinese Goats.

The casein alpha s1 (CSN1S1) gene encodes α-s1 casein, one of the proteins constituting milk, which affects milk performance, as well as improving the absorption of calcium and bone development in mammals. A previous study found that an 11-bp insertion/deletion (indel) of this gene strongly affected litter size in goats. However, to our knowledge, the relationships between this polymorphism and the milk performance and body measurement traits of goats have not been reported. In this paper, the previously identified indel has been recognized in three Chinese goat breeds, namely the Guanzhong dairy goat (GZDG; n = 235), Shaanbei white cashmere goat (SBWC; n = 1092), and Hainan black goat (HNBG; n = 278), and the following three genotypes have been studied for all of the breeds: insertion/insertion (II), deletion/deletion (DD), and insertion/deletion (ID). The allele frequencies analyzed signified that the frequencies of the "D" allele were higher (47.8%-65.5%), similar to the previous report, which indicates that this polymorphism is genetically stable in different goat breeds. Further analysis showed that this indel was markedly associated with milk fat content, total solids content, solids-not-fat content, freezing point depression, and acidity in GZDG (p < 0.05), and also affected different body measurement traits in all three breeds (p < 0.05). The goats with II genotypes had superior milk performance, compared with the others; however, goats with DD genotypes had better body measurement sizes. Hence, it may be necessary to select goats with an II or DD genotype, based on the desired traits, while breeding. Our study provides information on the potential impact of the 11-bp indel polymorphism of the CSN1S1 gene for improving the milk performance and body measurement traits in goats.

Goat SPEF2: Expression profile, indel variants identification and association analysis with litter size.

SPEF2 (sperm flagella 2 gene), also known as KPL2, plays important roles in germ cell development. The aim of this study was to investigate the mRNA expression profiles of goat SPEF2 among different tissues, as well as the relationship between SPEF2 indel polymorphisms and reproductive traits of 1104 Shaanbei white cashmere (SBWC) goats, and fully explore the expression characteristics and genetic effects of goat SPEF2. Results showed that SPEF2 was widely expressed and presented dynamic changes in goat testis at different developmental stages. SPEF2 mRNA expression level during meiosis phase was approximately equal to that during mitosis phase. Additionally, three potential insertion/deletion (indel) mutations were tested and verified by PCR and sequencing methods among 14 potential indel variant which are related to reproduction traits. For L-8 (NC_030827.1:g.38459098_38459107delTCAGTTCAGT: rs644277083), association test revealed that the goats with heterozygous ID had significantly more lambs than those with homozygous type II (P < 0.05). The influences of joint genotypes of L-8 and L-1 (NC_030827.1:g.38527458_38527459insGTTCACACCCAGTT) on goat reproductive traits were significant (P < 0.05). The association between combined genotypes and litter size showed that goats with homozygous genotypes had larger litter size than that of any of the other genotypes. Furthermore, through bioinformatics analysis, the remarkable influence of indel L-8 on traits might be caused by the change in AR (androgen receptor) binding site. These preliminary results are helpful to comprehensively study the function of SPEF2 and to provide theoretical references for SBWC goats breeding.

A novel missense mutation (L280V) within POU1F1 gene strongly affects litter size and growth traits in goat.

In mammals, POU1F1 is a key transcription factor that directly affects the secretion of pituitary hormones (GH, PRL, and TSH) and maintains growth and development. The aim of this study was to identify novel single nucleotide polymorphisms (SNPs) of the POU1F1 gene and evaluate the relations to litter size and growth performance in Shaanbei white cashmere (SBWC) goats. The ear tissues of female goats (n = 653) were collected, and the corresponding data were recorded. From direct DNA sequencing, a missense mutation (NC_030808.1:g.34236169A > C) was first detected in exon 6 of POU1F1 in SBWC goats that transformed the amino acid leucine into valine (L280V). Further analyses showed that the number of lambs of female goats with the TT genotype was significantly greater than that of female goats with the TG genotype (P < 0.01). In addition, a Chi-square test showed that the distributions of the two genotypes were remarkably different in the litters of two different sizes (P = 2.06E-06). Simultaneously, the frequency of the TT genotype for female goats with multiple lambs (≥2) was much greater than that of the TG genotype. When the relationships between growth traits and L280V were evaluated, the individuals with the TT genotype had superior growth traits compared with those of the TG genotype (P < 0.05), including for body height, body length, chest circumference, chest depth, chest width, height at hip cross, and cannon circumference. Notably, a positive relationship indicated that TT genotype female goats with improved growth traits tended to give birth to more lambs. We hypothesized that the mutation was in linkage disequilibrium with other responsible SNPs or affected the post-transcriptional regulation levels and then affected growth and litter size. This novel SNP may provide a functional genetic marker for improving economically valuable traits in goat breeding.

Relationship between SNPs of POU1F1 Gene and Litter Size and Growth Traits in Shaanbei White Cashmere Goats.

POU (Pit-Oct-Unc) class 1 homeobox 1 (POU1F1, or Pit-1) is a transcription factor that directly regulates pituitary hormone-related genes, as well as affects the reproduction and growth in mammals. Thus, POU1F1 gene was investigated as a candidate gene for litter size and growth performance in goats. In the current study, using direct DNA sequencing, c.682G > T, c.723T > G and c.837T > C loci were genotyped in Shaanbei white cashmere (SBWC) goats (n = 609), but c.876 + 110T > C was monomorphic. Besides, the c.682G > T locus was first identified by HinfI (Haemophilus influenzae Rf) restriction endonuclease. Association analysis results showed that the c.682G > T, c.837T > C loci and diplotypes were significantly associated with goat litter size (p < 0.05). The positive genotypes were GT and TT for the two SNPs, respectively, and the optimal diplotype was H3H7 (GTTT-TTTT). On the other hand, the c.682G > T, c.723T > G and c.837T > C strongly affected growth traits and body measurement indexes in SBWC goats (p < 0.05). The positive genotypes or allele of these SNPs were GT, G and TT, respectively. Additionally, the goats with H3H7 diplotype also had a greater growth status than others (p < 0.05). Here, individuals with same genotype had both a better litter size and growth traits, showing a positive correlation between these economic traits. Meanwhile, the positive genotypes of four SNPs were combined to obtain the optimal diplotype, which was also H3H7. These SNPs, especially the diplotype, could be used for the genomic selection of excellent individuals with a greater litter size and better growth status in goat breeding.

Goat PDGFRB: unique mRNA expression profile in gonad and significant association between genetic variation and litter size.

ß-Type platelet-derived growth factor receptor (PDGFRB) is a typical tyrosine kinase, as a candidate gene associated with reproduction. Its main roles include regulation of gonocytes (migration and proliferation) and of the cell cycle. The objectives of this study were to identify mRNA expression of the goat PDGFRB gene, as well as insertion/deletion (indel) variants and their association with litter size in 1122 healthy Shaanbei white cashmere goats. The results revealed that PDGFRB was widely expressed in all tested tissues, and the expression levels in testes at different developmental stages indicated a potential association with the mitosis-to-meiosis transition. Furthermore, the expression of PDGFRB was relatively higher in the ovary tissue of mothers of two lambs compared with mothers of single lamb. These results implied that PDGFRB was related to goat fertility. Meanwhile, two intronic indels, 5 bp (n = 501) and 10 bp (n = 1122), were identified. Statistical analysis revealed that only the 10 bp indel was associated with first-born litter size (n = 1122, p = 6.030 × 10-5), and that individuals of the genotype insertion/deletion had larger litter sizes than those of genotype insertion/insertion. Overall, these results indicated that the 10 bp indel of PDGFRB could be used in marker-assisted selection during goat genetic breeding.

Goat membrane associated ring-CH-type finger 1 (MARCH1) mRNA expression and association with litter size.

Membrane-associated ring-CH-type finger 1 (MARCH1), which mediates the ubiquitination of CD86 and MHC class II proteins, plays crucial roles in ruminant fecundity. To completely explore the functions of MARCH1 in goat reproduction, the mRNA expression of this gene were investigated in different tissues of goats. Moreover, we analyzed the association of three insertions and deletions (indels) within MARCH1 with litter size in a large population of Shaanbei white cashmere goats (n = 2844). It showed that MARCH1 was expressed in all examined tissues, including the spleen, brain, lungs, liver, muscles, and testis, of 14- and 56-day-old male goats and in the ovary tissues of female goats. However, MARCH1 expression levels in the testis and lungs were significantly different between the 14- and 56-day-old male goats. Therefore, we examined MARCH1 expression levels in the testis of male goats belonging to different developmental age groups, i.e., 0-, 14-, 28-, 42-, and 56-day-old male goats. Our results indicated a potential association between MARCH1 expression and mitosis-to-meiosis transition. Furthermore, we identified three novel 7-, 15-, and 18-bp indels in MARCH1 in the Shaanbei white cashmere goat population. The presence of the three indels significantly affected MARCH1 expression in the testis and ovary. Statistical analyses indicated that these indels were associated with first-born litter size (P < 0.05). A significant difference was observed in the genotype distribution of the three indels between single- and multi-lamb female goats (P < 0.05). Together, these findings suggest that MARCH1 plays a crucial role in fertility and that the three novel indels in the goat MARCH1 can be used as effective molecular markers for marker-assisted selection of goats for 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.

A novel indel within goat casein alpha S1 gene is significantly associated with litter size.

The ruminant casein gene family (CSNs, link as CSN1S1-CSN2-CSN1S2-CSN3) is characterized by diverse variations and has been extensively studied for ruminant milk traits, however, studies on insertion/deletion (indel) mutations within this gene family and their effects on prolificacy are extremely limited. This study aimed to detect possible novel indels within CSNs in an indigenous Chinese goat breed-Shaanbei White Cashmere goat (SBWC, n = 3047) and four other Chinese goat breeds (n = 1136) with varied litter size rates (105%-283%) and different estrus types (seasonal vs. perennial), as well as exploring the association between these potential indels and litter size. Only one novel 11-bp indel within the CSN1S1 gene was found. The association analyses uncovered that this novel indel was related to the first-birth litter size of SBWC population (n = 2690) (P < 1.0 E-8). Individuals with the II genotype (n = 676) had the best litter size when compared with those ID genotype (n = 1098) and DD genotype (n = 916) individuals. Animals with the II genotype were found to have higher relative expression level of CSN1S1 gene in the ovary (P < 0.01). Besides, Chi-square tests for different litter size and estrous cycle breeds showed that perennial-estrus breeds and multi-kids breeds had higher "I" allelic frequencies and "II" genotypic frequencies. These findings suggest the 11-bp indel within the CSN1S1 gene is significantly associated with reproduction traits and can be an effective molecular marker for litter size of goat breeding.

Insertion/Deletion Within the KDM6A Gene Is Significantly Associated With Litter Size in Goat.

A previous whole-genome association analysis identified lysine demethylase 6A (KDM6A), which encodes a type of histone demethylase, as a candidate gene associated to goat fecundity. KDM6A gene knockout mouse disrupts gametophyte development, suggesting that it has a critical role in reproduction. In this study, goat KDM6A mRNA expression profiles were determined, insertion/deletion (indel) variants in the gene identified, indel variants effect on KDM6A gene expression assessed, and their association with first-born litter size analyzed in 2326 healthy female Shaanbei white cashmere goats. KDM6A mRNA was expressed in all tissues tested (heart, liver, spleen, lung, kidney, muscle, brain, skin and testis); the expression levels in testes at different developmental stages [1-week-old (wk), 2, 3 wk, 1-month-old (mo), 1.5 and 2 mo] indicated a potential association with the mitosis-to-meiosis transition, implying that KDM6A may have an essential role in goat fertility. Meanwhile, two novel intronic indels of 16 bp and 5 bp were identified. Statistical analysis revealed that only the 16 bp indel was associated with first-born litter size (P < 0.01), and the average first-born litter size of individuals with an insertion/insertion genotype higher than that of those with the deletion/deletion genotype (P < 0.05). There was also a significant difference in genotype distributions of the 16 bp indel between mothers of single-lamb and multi-lamb litters in the studied goat population (P = 0.001). Consistently, the 16 bp indel also had a significant effect on KDM6A gene expression. Additionally, there was no significant linkage disequilibrium (LD) between these two indel loci, consistent with the association analysis results. Together, these findings suggest that the 16 bp indel in KDM6A may be useful for marker-assisted selection (MAS) of goats.

Generation of gene-modified goats targeting MSTN and FGF5 via zygote injection of CRISPR/Cas9 system.

Recent advances in the study of the CRISPR/Cas9 system have provided a precise and versatile approach for genome editing in various species. However, the applicability and efficiency of this method in large animal models, such as the goat, have not been extensively studied. Here, by co-injection of one-cell stage embryos with Cas9 mRNA and sgRNAs targeting two functional genes (MSTN and FGF5), we successfully produced gene-modified goats with either one or both genes disrupted. The targeting efficiency of MSTN and FGF5 in cultured primary fibroblasts was as high as 60%, while the efficiency of disrupting MSTN and FGF5 in 98 tested animals was 15% and 21% respectively, and 10% for double gene modifications. The on- and off-target mutations of the target genes in fibroblasts, as well as in somatic tissues and testis of founder and dead animals, were carefully analyzed. The results showed that simultaneous editing of several sites was achieved in large animals, demonstrating that the CRISPR/Cas9 system has the potential to become a robust and efficient gene engineering tool in farm animals, and therefore will be critically important and applicable for breeding.