age: 31 gender: Male tissue: Peripheral blood disease state: Normal
Treatment protocol
Four-milliliter EDTA-blood samples were collected at every visit and used for the genome-wide analysis of DNA methylation. For MZ 5B and E9 m, 5 and 6 independent whole blood samples were assessed for DNA methylation, respectively.
Growth protocol
Eleven monozygous twin pairs and 6 unrelated volunteers from China were recruited for the study . All participants had no health problems or diseases according to their self-reported health history records. Group A contained 10 pairs of MZ twins. Group B included a pair of MZ (male) twins and 6 unrelated individuals. Except subject H, all participants in Group B were recalled every 3 months for 9 months (0, 3, 6, and 9 m). Subject H was studied only at 0, 6, and 9 months.
Extracted molecule
genomic DNA
Extraction protocol
Buffy coat was extracted from peripheral blood, and genomic DNA was isolated using the QIAamp DNA Blood Mini Kit (Qiagen GmbH, Hilden, Germany) according to the manufacturer's instructions.
Label
Cy3, Cy5
Label protocol
standard Illumina protocol
Hybridization protocol
Bisulphite converted DNA was amplified, fragmented and hybridised to Illumina Infinium Human Methylation450 Beadchip using standard Illumina protocol
Scan protocol
Arrays were imaged using BeadArray Reader using standard recommended Illumina scanner setting
Description
Normal blood sample used for longitudinal study #C-1
Data processing
The signal intensities and detection P values were extracted using GenomeStudio with no background subtraction or control normalization. The probes located on the X and Y chromosomes, probes containing SNP(s) or non-CpG loci, and probes with a detection P value exceeding 0.05 or missing β-values in any of the samples were removed from all individuals in the same group. After removal of these probes, 77.3% (375,324) and 76.0% (369,187) of the 485,577 CpG probes were tested for Groups A and B, respectively. The data were processed using the Bioconductor lumi package (version 2.12) and BMIQ (version 1.0) written in the R programming language. Color-bias adjustment (Col.Adj) and quantile normalization (QN) were carried out on the signal intensities in the Bioconductor lumi package to remove the batch effect from the experiment; subsequently, the probe type-bias adjustment was performed on the β-values using BMIQ. The β-values were transformed into M-values.
