Integration of whole-genome DNA methylation data with RNA sequencing data to identify markers for bull fertility
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ABSTRACT: Predicting dairy bull fertility is a current challenge for the dairy industry. The goal of this study was to integrate DNA methylation data with previously published RNA sequencing results in order to identify candidate markers for sire fertility.
Project description:High fertility and low fertility bulls were screened from the a 6000 bull database and then identify the sperm-derived DMR and DMC that assoiated with bull ferrtility via whole genome methtlation sequencing
Project description:Pregnancy rates for elite bulls used in artificial insemination (AI) can vary significantly and therefore the identification of molecular markers for bull fertility and targets to improve bull selection is important. β-defensins are peptides with diverse regulatory roles in sperm function across multiple species. To explore the functional impact of DEFB103 CNV on the uterine response in vivo, 18 heifers were inseminated with sperm from bulls categorized by low, intermediate, and high CN levels. Transcriptomic analysis of uterine tissue collected 12 hours after insemination revealed significant differential expression of 58 genes (FDR<0.1) related to sperm migration, immune signaling, and chemotaxis. These findings highlight the significant role of DEFB103 CN in both sperm function and the uterine response to bull sperm, suggesting its potential influence on pregnancy outcomes in cattle.
Project description:Purpose: Screening the sperm sncRNAs that are responsible for dairy cattle fertility is of great interest, however, exploring the fertility-associated sncRNAs in sperm and linking them with the epigenetic inheritance in bovine has not been performed yet. Here in this study, we hypothesized that some sncRNAs in bovine sperm have a great potential to be linked with direct and immediate bull fertility data and could later influence the embryo and possibly impacting the daughter fertility. Methods: 12 bovine cryopreserved semen (high bull fertility, n=3 VS low bull fertility, n=3; high daughter fertility, n=3 vs low daughter fertility, n=3) that came from a pre-filtered 100 bull list (Figure 1) had been selected to extract total sperm RNA, the somatic cell lysis buffer had been added during the RNA extraction process to avoid the somatic cell pollution. The maternal and other confounding factors had been taken into consideration during the calculation of the phenotype criteria index.After the library construction, the library size that was smaller than 200 base pairs (adapter size around 125 nt) had been cut and sent for next-generation sequencing Results: bull fertility and daughter fertility related sncRNAs had been identified. Conclusions: providing promising epigenetic biomarker for cattle fertility improvement in the future, although these small non-coding RNAs need to be validated in larger sample sizes before being used as biomarkers.
Project description:The aim of this study was to examine the effect of sire fertility status on conceptus-induced changes in the endometrial transcriptome. Holstein Friesian bulls (3 High fertility, HF, 3 Low fertility, LF) were selected from the Irish national population of AI bulls (minimum of 500 inseminations/bull) based on adjusted fertility scores (HF: +4.37% and LF: -12.7%; mean = 0%). To generate elongated conceptuses, Day 7 blastocysts produced in vitro using sperm from these six bulls were transferred in groups of 5-10 to synchronized heifers (n=7 heifers per bull; total 42 heifers). Conceptuses were recovered following slaughter on Day 15 (recovery rate: HF 59.4% vs. LF 45.0%; P<0.05). In parallel, Day 15 endometrial explants were recovered from synchronized cyclic heifers (n=4). Explants from each heifer were co-cultured for 6 h in RPMI medium with (i) nothing, control (ii) 100 ng/ml ovine recombinant interferon tau (IFNT) (iii) a single conceptus from each high fertility bull, or (iv) a single conceptus from each low fertility bull. To minimize variation, explants from the same uterus were used across all treatments, replicated across 4 heifers. After 6 h, explants were snap frozen and stored at -80°C. Extracted mRNA was subjected to RNA-seq (Illumina NextSeq 500) and the resulting data were analyzed through a bioinformatic pipeline with R software.
Project description:Embryo development, In vitro fertilization, Bull fertility, Polyspermy, Proteomics Project description: The correlation between sperm traits, fertilization and embryonic development outcomes were investigated by means of functional in vitro assays and mass spectrometry-based proteomics experiments. Spermatozoa from four independent bulls, as well as approx.. 20 cells at 2-cell embryonic stages and full blastocysts (approx. 250 cells) derived from in vitro fertilization of oocytes with spermatozoa from these foru bulls were analyzed by MS-based proteomics.
Project description:Prediction of male or semen fertility potential remains a persistent challenge that has yet to be fully resolved. This work analyzed several in vitro parameters and proteome of spermatozoa in bulls cataloged as high (HF; n=5) and low field (LF; n=5) fertility after more than a thousand artificial inseminations. Sperm motility was evaluated by Computer-Assisted Sperm Analysis. Sperm viability, mitochondrial membrane potential (MMP), and reactive oxygen species (mROS) of spermatozoa were assessed by flow cytometry. Proteome was evaluated by SWATH-MS procedure. Spermatozoa of HF bulls showed significantly higher total motility than the LF group (41.4% vs. 29.7%). Rates of healthy sperm (live, high MMP, and low mROS) for HF and LF bull groups were 49% and 43%, respectively (p > 0.05). Spermatozoa of HF bulls showed higher presence of differentially abundant proteins (DAPs) related to both energy production (COX7C), mainly OXPHOS pathway, and to the development of structures linked with the motility process (TPPP2, SSMEM1 and SPAG16). Furthermore, we observed that EQTN, together with other DAPs related to the interaction with the oocyte, were overrepresented in HF bull spermatozoa. The biological processes related to protein processing, catabolism, and protein folding were found to be overrepresented in LF bull sperm in which the HSP90AA1 chaperone was identified as the most DAP
Project description:high daughter fertility and low daughter fertility bulls were screened from the private bull database and then identify the sperm-derived DMR and DMC that associated with daughter fertility via whole genome methylation sequencing
Project description:Bull fertility is an important economic trait, and the use of subfertile semen for artificial insemination decreases the global efficiency of the breeding sector. Although the analysis of semen functional parameters can help to identify infertile bulls, no tools are currently available to enable precise predictions and prevent the commercialization of subfertile semen. Because male fertility is a multifactorial phenotype that is dependent on genetic, epigenetic, physiological and environmental factors, we hypothesized that an integrative analysis might help to refine our knowledge and understanding of bull fertility. We combined -omics data (genotypes, sperm DNA methylation at CpGs and sperm small non-coding RNAs) and semen parameters measured on a large cohort of 98 Montbéliarde bulls with contrasting fertility levels. Multiple Factor Analysis was conducted to study the links between the datasets and fertility. Four methodologies were then considered to identify the features linked to bull fertility variation: Logistic Lasso, Random Forest, Gradient Boosting and Neural Networks. Finally, the features selected by these methods were annotated in terms of genes, to conduct functional enrichment analyses. The less relevant features in -omics data were filtered out, and MFA was run on the remaining 12,006 features, including the 11 semen parameters and a balanced proportion of each type of-omics data. The results showed that unlike the semen parameters studied the-omics datasets were related to fertility. Biomarkers related to bull fertility were selected using the four methodologies mentioned above. The most contributory CpGs, SNPs and miRNAs targeted genes were all found to be involved in development. Interestingly, fragments derived from ribosomal RNAs were overrepresented among the selected features, suggesting roles in male fertility. These markers could be used in the future to identify subfertile bulls in order to increase the global efficiency of the breeding sector.