Comparative analysis of ovarian transcriptomes between prolific and non-prolific goat breeds via high-throughput sequencing

Multiomic meta-analysis suggests a correlation between steroid hormone-related genes and litter size in goats

Litter size is a key indicator of production performance in livestock. However, its genetic basis in goats remains poorly understood. In this work, a genome-wide selection sweep analysis (GWSA) on 100 published goat genomes with different litter rates was performed for the first time to identify candidate genes related to kidding rate. This analysis was combined with the public RNA-sequencing data of ovary tissues (follicular phase) from high- and low-yielding goats. A total of 2278 genes were identified by GWSA. Most of these genes were enriched in signaling pathways related to ovarian follicle development and hormone secretion. Moreover, 208 differentially expressed genes between groups were obtained from the ovaries of goats with different litter sizes. These genes were substantially enriched in the cholesterol and steroid synthesis signaling pathways. Meanwhile, the weighted gene co-expression network was used to perform modular analysis of differentially expressed genes. The results showed that seven modules were reconstructed, of which one module showed a very strong correlation with litter size (r = -0.51 and p-value <0.001). There were 51 genes in this module, and 39 hub genes were screened by Pearson's correlation coefficient between core genes > 0.4, correlation coefficient between module members > 0.80 and intra-module connectivity ≥5. Finally, based on the results of GWSA and hub gene Venn analysis, seven key genes (ACSS2, HECW2, KDR, LHCGR, NAMPT, PTGFR and TFPI) were found to be associated with steroid synthesis and follicle growth development. This work contributes to understanding of the genetic basis of goat litter size and provides theoretical support for goat molecular breeding.

Transcriptomic Analysis of the Developing Testis and Spermatogenesis in Qianbei Ma Goats

Reproductive competence in male mammals depends on testicular function. Testicular development and spermatogenesis in goats involve highly complex physiological processes. In this study, six testes were, respectively, obtained from each age group, immature (1 month), sexually mature (6 months) and physically mature (12 months old) Qianbei Ma goats. RNA-Seq was performed to assess testicular mRNA expression in Qianbei Ma goats at different developmental stages. Totally, 18 libraries were constructed to screen genes and pathways involved in testis development and spermatogenesis. Totally, 9724 upregulated and 4153 downregulated DEGs were found between immature (I) and sexually mature (S) samples; 7 upregulated and 3 downregulated DEGs were found between sexually mature (S) and physically mature (P) samples, and about 4% of the DEGs underwent alternative splicing events between I and S. Select genes were assessed by qRT-PCR, corroborating RNA-Seq findings. The detected genes have key roles in multiple developmental stages of goat testicular development and spermatogenesis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine differentially expressed genes (DEGs). GO analysis revealed DEGs between S and P contributed to "reproduction process", "channel activity" and "cell periphery part" between I and S, and in "ion transport process", "channel activity" and "transporter complex part". KEGG analysis suggested the involvement of "glycerolipid metabolism", "steroid hormone biosynthesis" and "MAPK signaling pathway" in testis development and spermatogenesis. Genes including IGF1, TGFB1, TGFBR1 and EGFR may control the development of the testis from immature to sexually mature, which might be important candidate genes for the development of goat testis. The current study provides novel insights into goat testicular development and spermatogenesis.

Association Analysis of PRKAA2 and MSMB Polymorphisms and Growth Traits of Xiangsu Hybrid Pigs

In this study, Xiangsu hybrid pig growth traits were evaluated via PRKAA2 and MSMB as candidate genes. Sanger sequencing revealed three mutation sites in PRKAA2, namely, g.42101G>T, g.60146A>T, and g.61455G>A, and all these sites were intronic mutations. Moreover, six mutation sites were identified in MSMB: intronic g.4374G>T, exonic g.4564T>C, exonic g.6378G>A, exonic g.6386C>T, intronic g.8643G>A, and intronic g.8857A>G. Association analysis revealed that g.42101G>T, g.60146A>T, g.61455G>A, g.4374G>T, g.4564T>C, g.6378G>A, g.6386C>T, g.8643G>A, and g.8857A>G showed different relationship patterns among body weight, body length, body height, chest circumference, abdominal circumference, tube circumference, and chest depth. Real-time polymerase chain reaction results revealed that the expression of PRKAA2 was highest in the longissimus dorsi muscle, followed by that in the heart, kidney, liver, lung, and spleen. The expression of MSMB was highest in the spleen, followed by that in the liver, kidney, lung, heart, and longissimus dorsi muscle. These results suggest that PRKAA2 and MSMB can be used in marker-assisted selection to improve growth related traits in Xiangsu hybrid pigs, providing new candidate genes for Pig molecular breeding.

Integrated analysis of lncRNA and gene expression in longissimus dorsi muscle at two developmental stages of Hainan black goats

It is deemed that meat quality of kids’ is better than that of adults’ for Hainan black goat. Generally, meat quality is affected by many indicators, such as intramuscular fat (IMF) content, muscle fiber diameter and shear force. It is indicated that long non-coding RNAs (lncRNAs) play essential roles in meat quality of goats. However, it is unclear whether and how lncRNAs and genes play their roles in meat quality of Hainan Black goats. Here, we firstly compared the meat quality between two-month-old kids (kids) and adult goats (adults). Then, the lncRNA-seq and RNA-seq data were integrated and analyzed to explore the potential functions of lncRNAs and genes. The results showed that adults’ IMF content and muscle fiber diameter were extremely significantly higher than that of kids (P<0.01). For the sequenced data, average 84,970,398, and 83,691,250 clean reads were obtained respectively for Kids and adults, among which ~96% were mapped to the reference genome of goats. Through analyzing, 18,242 goat annotated genes, 1,429 goat annotated lncRNAs and 2,967 novel lncRNAs were obtained. Analysis of differential expression genes (DEGs) and lncRNAs (DELs) showed that 328 DEGs and 98 DELs existed between kids and adults. Furthermore, functional enrichment analysis revealed that a number of DEGs and DELs were mainly associated with IMF. Primarily, DGAT2 expressed higher in adults than that in kids and CPT1A expressed higher in kids than that in adults. Both of them were overlapped by DEGs and targets of DELs, suggesting the two DEGs and the DELs targeted by the two DEGs might be the potential regulators of goat IMF deposition. Taken together, our results provide basic support for further understanding the function and mechanism of lncRNAs and genes in meat quality of Hainan black goats.

Identification of differentially expressed genes and signalling pathways in the ovary of higher and lower laying ducks

1. Ovarian transcriptomic profiling between birds showing high egg number (HEN) and birds of low egg number (LEN) in Longyan Shan-ma ducks at 71 weeks of age was carried out using Illumina Hiseq 2500 technology. 2. A total of 343 differentially expressed genes (DEGs, 269 upregulated and 74 downregulated) were identified between HEN and LEN ovaries. These DEGs were enriched in 30 Gene Ontology terms. Pathway functional analysis found that the DEGs were enriched in 10 metabolic pathways (P < 0.05), one of which was regulation of the actin cytoskeleton pathway (Q < 0.05). 3. Three integrin family genes, ITGB2, ITGB5 and ITGA8 were differentially expressed in the RNA-seq and qPCR experiments. 4. The DEGs and signalling pathways identified in ovarian tissue in this study provide new insights into high egg production in Longyan Shan-ma duck.

Identification of transcriptome differences in goat ovaries at the follicular phase and the luteal phase using an RNA-Seq method

The ovaries, the main female reproductive organs, directly mediate ovulation and reproductive hormone secretion. These complex physiological processes are regulated by multiple genes and pathways. However, there is a lack of research on goat ovaries, and the molecular mechanisms underlying the signaling pathways remain unclear. In this study, Illumina HiSeq 4000 sequencing was used to sequence the transcriptomes of goat ovaries. The expression patterns of differentially expressed mRNAs in goat ovaries at both the follicular and luteal phases were determined by bioinformatics analysis. A total of 1,122, 014, 112 clean reads were obtained, and 3770 differentially expressed mRNAs were identified for further analysis. There were 1727 and 2043 upregulated mRNAs in the luteal phase and follicular phase, respectively. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, some mRNAs that were highly expressed in ovaries during the luteal phase, such as HSD17B7, 3BHSD, and SRD5A2, may be related to the synthesis of progesterone. In addition, some mRNAs that were highly expressed in ovaries during the follicular phase, such as RPL12, RPS13 and RPL10, are related to the growth and maturation of oocytes. Taken together, the findings of this study provide genome-wide mRNA expression profiles for goat ovaries at the follicular and luteal phases and identify mRNAs associated with goat hormone secretion and follicular development. In addition, this study provides a theoretical basis for further investigation of goat reproductive regulation.

Comparative and selection sweep analysis of CNV was associated to litter size in Dazu black goats

This study aims to identify the relative Copy number variation (CNV) associated with the litter size of Dazu black goats based on the unpublished CNV analytical results of our previously published sequencing data, in which the litter-size groups were classified into extreme low- and high-yield groups. Firstly, to compare the existence of valuable CNV in Dazu black goats with different fertility levels with mixed pools. We obtained 4992 and 4888 CNVs from the HY and LY, which overlapping 1461 genes, and classified on the original CNV type. Three genes [LOC108633278, PPP1R12A, and YIPF4] were observed in the intersection between the HY deletion and the LY duplication groups. Secondly, on individuals level, we identified a novel candidate CNV (Chr1_50215501, F_ST = 0.148, V_ST = 0.347) from 214 autosomal credible CNVs to be significant with litter size in the Dazu black goat, which located in the CBLB gene. This finding indicates the CBLB gene may affect the litter size of the Dazu black goats through structural variations, and Chr1_50215501 can be an effective genetic marker for marker-assisted selection breeding, and this study was also helps understand the molecular mechanism related to the goat litter size.

Comprehensive analysis of mRNAs and miRNAs in the ovarian follicles of uniparous and multiple goats at estrus phase

Background

Fertility is an important economic trait in the production of meat goat, and follicular development plays an important role in fertility. Although many mRNAs and microRNAs (miRNAs) have been found to play critical roles in ovarian biological processes, the interaction between mRNAs and miRNAs in follicular development is not yet completely understood. In addition, less attention has been given to the study of single follicle (dominant or atretic follicle) in goats. This study aimed to identify mRNAs, miRNAs, and signaling pathways as well as their interaction networks in the ovarian follicles (large follicles and small follicles) of uniparous and multiple Chuanzhong black goats at estrus phase using RNA-sequencing (RNA-seq) technique.

Results

The results showed that there was a significant difference in the number of large follicles between uniparous and multiple goats (P < 0.05), but no difference in the number of small follicles was observed (P > 0.05). For the small follicles of uniparous and multiple goats at estrus phase, 289 differentially expressed mRNAs (DEmRNAs) and 16 DEmiRNAs were identified; and for the large follicles, 195 DEmRNAs and 7 DEmiRNAs were identified. The functional enrichment analysis showed that DE genes in small follicles were significantly enriched in ovarian steroidogenesis and steroid hormone biosynthesis, while in large follicles were significantly enriched in ABC transporters and steroid hormone biosynthesis. The results of quantitative real-time polymerase chain reaction were consistent with those of RNA-seq. Analysis of the mRNA-miRNA interaction network suggested that CD36 (miR-122, miR-200a, miR-141), TNFAIP6 (miR-141, miR-200a, miR-182), CYP11A1 (miR-122), SERPINA5 (miR-1, miR-206, miR-133a-3p, miR-133b), and PTGFR (miR-182, miR-122) might be related to fertility, but requires further research on follicular somatic cells.

Conclusions

This study was used for the first time to reveal the DEmRNAs and DEmiRNAs as well as their interaction in the follicles of uniparous and multiple goats at estrus phase using RNA-seq technology. Our findings provide new clues to uncover the molecular mechanisms and signaling networks of goat reproduction that could be potentially used to increase ovulation rate and kidding rate in goat.

Characterization of the hypothalamo-pituitary-gonadal axis in low and high egg producing turkey hens

Variation in egg production exists in commercial turkey hens, with low egg producing hens (LEPH) costing more per egg produced than high egg producing hens (HEPH). Egg production correlates with ovulation frequency, which is governed by the hypothalamic-pituitary-gonadal (HPG) axis. Ovulation is stimulated by a preovulatory surge (PS) of progesterone and luteinizing hormone, triggered by gonadotropin releasing hormone release and inhibited by gonadotropin inhibiting hormone. Differences between LEPH and HEPH were characterized by determining HPG axis plasma hormone profiles and mRNA levels for key genes, both outside and inside of the PS (n = 3 per group). Data were analyzed with a 2-way ANOVA using the mixed models procedure of SAS. In the HPG axis, plasma progesterone levels were not affected by egg production level but were elevated during the PS. In contrast, plasma estradiol levels were higher in HEPH than in LEPH but were not associated with the PS. LEPH exhibited decreased gene expression associated with ovulation stimulation and increased gene expression associated with ovulation inhibition in the hypothalamus and pituitary. In ovarian follicle cells, LEPH displayed decreased gene expression associated with progesterone, androgen, and estradiol production in the F1 follicle granulosa cells, F5 theca interna cells, and small white follicle cells, respectively. Different degrees of stimulation and inhibition within all tissues of the HPG axis were noted between LEPH and HEPH turkey hens, with HEPH showing higher expression of genes related to ovulation and steroidogenesis.