Comparison of the genome-wide DNA methylation profiles between fast-growing and slow-growing broilers
ABSTRACT: Chicken growth traits are important in poultry production, however, little is known for its regulatory mechanism at epigenetic level. Therefore, this study aims to compare DNA methylation profiles between fast- and slow-growing broilers in order to identify candidate genes underlying chicken growth. Methylated DNA immunoprecipitation-sequencing (MeDIP-seq) was used to investigate the genome-wide DNA methylation pattern in high and low tails of Recessive White Rock (WRRh, WRRl) and that of Xinhua Chickens (XHh, XHl). The results showed that the average of methylation density was the lowest in CGIs followed by promoters. Within the gene body, the methylation density of introns was higher than UTRs and exons. Moreover, different methylation levels were observed in different repeat types with the highest in LINE/CR1. Methylated CGIs were prominently distributed in the intergenic regions and were enriched in the size range of 200-300 bp. In total 13,294 methylated genes were found in four samples, including 4,085 differentially methylated genes between WRRh and WRRl, 5,599 between XHh and XHl, 4,204 between WRRh and XHh, as well as 7,301 between WRRl and XHl. Moreover, 132 differentially methylated genes related to growth and metabolism were observed in both inner contrasts (WRRh Vs. WRRl and XHh Vs. XHl), whereas 129 differentially methylated genes related to growth and metabolism were found in both across-breed contrasts (WRRh Vs. XHh and WRRl Vs. XHl). Further analysis showed that overall 75 genes exhibited altered DNA methylation in all four contrasts, which included some well-known growth factors of IGF1R, FGF12, FGF14, FGF18, FGFR2, and FGFR3. In addition, we further validate the MeDIP-seq results by bisulfite sequencing in some regions. 12 Breast muscle samples were collected from two breeds of different growth rate, Recessive White Rock (WRR) and Xinhua Chickens (XH). Each breed included low and high-weight groups and 3 samples from each group were pooled equally for methylated DNA immunoprecipitation-sequencing (MeDIP-seq).
Project description:Long non-coding RNAs (lncRNAs) can have potential roles in development of tissues and organs. We selected breast muscle of fast-growing White Recessive Rock chicken (WRR) and slow-growing Xing Hua chicken (XH) to identify lncRNA transcripts by LncRNA-Seq. This study identified 21,993 novel lncRNAs. Among 7,339 differentially expressed lncRNAs, 723 up-regulated and 6,616 down-regulated lncRNAs were found in WRR compared with XH. Of them, five novel lncRNA were antisense transcripts for growth-related genes CACNA1D (unigene 14689_all), IL4I1 (unigene 15355_all), LEF-1 (unigene 19525_all) and FABP1 (unigenes 17536_all and 17537_all) respectively. Meanwhile, 12 other novel lncRNAs were found in the intron or downstream of some known growth-related genes (IGF1, IGF2BP2, IGF2BP3, CACNA1D, IL4I1, LEF-1 and FABP1). In addition, 4,043 SSRs and 200,049 SNPs were identified. Our data revealed the global lncRNA expression pattern in muscle tissue, and contributed a useful genomic resource towards studying the effects of lncRNAs in regulating chicken growth. Two RNA pool for WRR and XH strains
Project description:To investigate the function of miRNAs in chicken growth, breast muscle tissues of the two-tail samples (highest and lowest body weight) from Recessive White Rock (WRR) and Xinghua Chickens (XH) were performed on high throughput small RNA deep sequencing. In this study, a total of 921 miRNAs were identified, including 733 known mature miRNAs and 188 novel miRNAs. There were 200, 279, 257 and 297 differentially expressed miRNAs in the contrasts of WRRh Vs. WRRl, WRRh Vs. XHh, WRRl Vs. XHl, and XHh Vs. XHl group, respectively. A total of 22 serious differentially expressed miRNAs (fold change > 2 or < 0.5; P-value < 0.05; q-value < 0.01) which also have abundant expression (read counts > 1,000) were found in our contrasts. As far as two contrasts (WRRh Vs. WRRl, and XHh Vs. XHl) are concerned, we found 80 common differentially expressed miRNAs, meanwhile 110 miRNAs were found in WRRh Vs. XHh and WRRl Vs. XHl. Furthermore, only 26 common miRNAs were identified among all of four contrasts. Examination of miRNA profiles in two-tail samples of WRR and XH strains.
Project description:Methylated DNA immunoprecipitation sequencing (MeDIP-Seq) is a widely used approach to study DNA methylation genome-wide. Here, we present a novel MeDIP-Seq protocol compatible with the Ion Torrent semiconductor-based sequencing platform that is scalable and accurately identifies sites of differential DNA methylation. Additionally, we demonstrate that the high-throughput data derived from MeDIP-Seq on the Ion Torrent platform provides adequate coverage of CpG cytosines, the methylation states of which we validated at single-base resolution on the Infinium HumanMethylation450K Beadchip array. We applied this integrative approach to further investigate the role of DNA methylation in alternative splicing and to profile 5-mC and 5-hmC variants of DNA methylation in normal human brain tissue that we observed localize over distinct genomic regions. These applications of MeDIP-Seq on the Ion Torrent platform have broad utility and add to the current methodologies for profiling genome-wide DNA methylation states in normal and disease conditions. MeDIP-Seq on Ion Torrent Platform in HCT116 and Human Brain
Project description:Epigenetic modification plays important roles in plant and animal development. DNA methylation can impact the transposable element (TE) silencing, gene imprinting and regulate gene expression.Through a genome-wide analysis, DNA methylation peaks were respectively characterized and mapped in maize embryo and endosperm genome. Distinct methylation level across maize embryo and endosperm was observed. The maize embryo genome contained more DNA methylation peaks than endosperm. However, the endosperm chloroplast genome contained more DNA methylation peaks to compare with the embryo chloroplast genome. DNA methylation regions were characterized and mapped in genome. More CG island (CGI) shore are methylated than CGI in maize suggested that DNA methylation level is not positively correlated with CpG density. The DNA methylation occurred more frequently in the promoter sequence and transcriptional termination region (TTR) than other regions of the genes. The result showed that 99% TEs we characterized are methylated in maize embryo, but some (34.8%) of them are not methylated in endosperm. Maize embryo and endosperm exhibit distinct pattern/level of methylation. The most differentially methylated two regions between embryo and endosperm are High CpG content promoters (HCPs) and high CpG content TTRs (HCTTRs). DNA methylation peaks distinction of mitochondria and chloroplast DNA were less than the nucleus DNA. Our results indicated that DNA methylation is associated with the gene silencing or gene activation in maize endosperm and embryo. Many genes involved in embryogenesis and seed development were found differentially methylated in embryo and endosperm. We found 17 endosperm-specific expressed imprinting genes were hypomethylated in endosperm and were hypermethylated in embryo. The expression of a maize DEMETER -like (DME-like) gene and MBD101 gene (MBD4 homolog) which direct bulk genome DNA demethylation were higher in endosperm than in embryo. These two genes may be associated with the distinct methylation level across maize embryo and endosperm.The methylomes of maize embryo and endosperm was obtained by MeDIP-seq method. The global mapping of maize embryo and endosperm methylation in this study broadened our knowledge of DNA methylation patterns in maize genome, and provided useful information for future studies on maize seed development and regulation of metabolic pathways in different seed tissues. Examination of DNA methylated modifications in 2 maize tissues.
Project description:We report the genome-wide DNA methylation mapping of chicken by methylated DNA immunoprecipitation following by highthroughput sequencing, and the gene expression profile of chicken by RNA-seq. For meDIP-seq, about 17,202,074 to 27,501,760 reads were generated for the tissue and liver tissues of the red jungle fowl and the avian broiler each. We found that compared with the red jungle fowl, DNA methylation in muscle tissue of the avian broiler, showed dramatically decline on a genome-wide scale. Furthermore, the length of the highly methylated regions (HMRs) has become shorter in the avian broiler, which has suffered intense artificial selection. In addition to the global changes in DNA methylation, transcriptome-wide analysis of the two breeds of chicken revealed that the patterns of gene expression in the domestic chicken have undergone a specific bias towards a pattern that is more suited to human-made environments with variable expression in certain gene functions, such as immune response and fatty acid metabolism. Our results demonstrated a potential role of epigenetic modification in animal domestication besides the genetic variations. Examination of whole genome DNA methylation status in liver and muscle of two chicken breeds.
Project description:Malignant melanoma is the most fatal skin cancer with a high degree of genetic and epigenetic aberrations. To investigate the role of DNA methylation on melanoma heterogeneity, we performed methylated DNA immunoprecipitation (MeDIP) microarray analysis of 10 primary melanoma cell cultures. methylated DNA immunoprecipitation (MeDIP) microarray analysis of 10 primary melanoma cell cultures
Project description:Genomic imprinting describes the expression of a subset of mammalian genes from one parental chromosome. The parent-of-origin specific expression of imprinted genes relies on DNA methylation of CpG-dinucleotides at differentially methylated regions (DMRs) during gametogenesis. We identified the paternally methylated DMR at human chromosome 2 near the imprinted ZDBF2 gene using a methylated-DNA immunoprecipitation-on-chip (meDIP-on-chip) method applied to DNA from sperm. To analyze whether or not the GPR1-ZDBF2 DMR is conserved in human genome, methylation analysis of human sperm sample was performed using MeDIP and genome tiling array.
Project description:Genomic imprinting describes the expression of a subset of mammalian genes from one parental chromosome. The parent-of-origin specific expression of imprinted genes relies on DNA methylation of CpG-dinucleotides at differentially methylated regions (DMRs) during gametogenesis. We identified the paternally methylated DMRs at mouse chromosome 1 near the imprinted Zdbf2 gene using a methylated-DNA immunoprecipitation-on-chip (meDIP-on-chip) method applied to DNA from parthenogenetic (PG)- and androgenetic (AG)-derived cells and sperm. To identify novel DMRs, genome-wide methylation analysis of three samples were performed using MeDIP and whole genome tiling array.
Project description:Genome-wide methylation analysis was performed by methylated DNA immunoprecipitation (MeDIP)-CpG island (CGI) microarray analysis to identify candidate CGIs specifically methylated in mouse colon tumors associated with colitis. We sucessfully identified 23 candidate CGIs methylated in tumors. Two samples were analyzed by MeDIP-CGI microarray. One is a pool of two AOM/DSS-induced colon tumors in BALB/c mice and another is a pool of two normal colonic epithelial cell samples obtained from untreated BALB/c mice by the crypt isolation technique. The pool of normal colonic epithelial cell samples was used as reference. Dye-swaps were not perfromed. The methylation statuses of CGIs identified by microarray were confirmed by another method, methylation-specific PCR.
Project description:Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly population worldwide. Recent studies have demonstrated strong genetic associations between AMD and single nucleotide polymorphisms (SNPs) within genes such as CFH and HTRA1. However, we found monozygotic twins had discordant AMD phenotypes (one with disease, the other without disease), suggesting that an epigenetic mechanism may control the pathogenesis of AMD. We obtained genomic DNA from the twins' peripheral blood mononuclear cells (PBMCs) and subjected it to DNA methylation-chip analysis (MeDIP-chip) that profiled genome-wide DNA methylation patterns on promoters of all genes and microRNAs. Our MeDIP-chip analysis identified 256 genes with hypo-methylated promoters only in the twins with AMD and 744 genes with hyper-methylated promoters only in the twins with AMD. Importantly, the promoter region of IL17RC was associated with hypo-methylated CpG sites only in the twins with AMD but not in the twins without AMD. Two pairs of twins with discordant AMD phenotypes. MeDIP-chip analysis of DNA methylation patterns in PBMCs.