70: MSA and ternary-code DNA methylation

Goldberg DC et al., Cell Genomics - This episode examines the methylation screening array (MSA), a compact Infinium BeadChip optimized for trait-associated and cell-type CpGs and compatible with matched 5hmC profiling to enable scalable EWAS, cell deconvolution, and aging analyses. Key terms: DNA methylation, 5hmC, Infinium array, EWAS, epigenetic clock.

Study Highlights:
The authors developed the MSA to enable high-throughput profiling of ternary-code cytosine modifications (5mC, 5hmC, and unmodified C) across many human samples. They generated matched 5mC/5hmC atlases across multiple tissues and immune cell types and validated array accuracy against sequencing standards. Analyses show 5hmC is enriched at enhancers and gene bodies, complements 5mC in defining tissue identity, correlates positively with gene expression, is diluted in proliferative tissues, and contributes to epigenetic clock signals.

Conclusion:
The MSA is an accurate, reproducible, and scalable platform that maps ternary-code methylation across human tissues and highlights complementary roles of 5hmC and 5mC in tissue identity, aging, and trait-associated signals, enabling population-scale methylation screening.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Scalable screening of ternary-code DNA methylation dynamics associated with human traits

First author:
Goldberg DC

Journal:
Cell Genomics

DOI:
10.1016/j.xgen.2025.100929

Reference:
Goldberg DC, Cloud C, Lee S.M., et al. Scalable screening of ternary-code DNA methylation dynamics associated with human traits. Cell Genomics. 2025;5:100929. https://doi.org/10.1016/j.xgen.2025.100929

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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Episode link: https://basebybase.com/episodes/papercast-base-by-base-70-encoding-corrupted

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2025-07-09.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript’s coverage of MSA design and targets, 5mC/5hmC/3-state methylation, the bACE sequencing approach, tissue specificity and aging clocks, and blood-based cell deconvolution, plus study limitations.
- transcript topics: Ternary-code DNA methylation (5mC, 5hmC, unmodified C); MSA design and probe targeting; bACE protocol and 5hmC discrimination; Tissue-specific 5hmC/5mC distributions; 5hmC aging dynamics and epigenetic clocks; Blood-based immune cell deconvolution and age/sex effects

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Existence of a tri-state DNA methylation encoding (5mC, 5hmC, unmodified cytosine)
- MSA design comprises 284,317 unique probes across 269,094 genomic loci, with 145,426 loci overlapping EPICv2
- bACE protocol enables 5hmC profiling by...