DNA methylation

Scientific

/ mĕth′ə-lā′shən /

The modification of a strand of DNA after it is replicated, in which a methyl (CH ₃) group is added to any cytosine molecule that stands directly before a guanine molecule in the same chain. Since methylation of cytosines in particular regions of a gene can cause that gene's suppression, DNA methylation is one of the methods used to regulate the expression of genes.

DNA methylation Cultural

The chemical reactions that place a methyl group (a combination of one carbon atom and three hydrogen atoms) at a particular spot on DNA during organismal development. The effect of this process is probably to “turn off” various genes during the process of cellular differentiation, causing the cell to develop into a specific type.

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It is thought that during cloning, the methyl groups are removed from the DNA, turning the genes back “on” again.

There is evidence that embryonic stem cells are cells in which this process has not yet occurred.

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DNA methylation

More recent research has explored how age-related changes in hypothalamic DNA methylation and hormone signaling could contribute to neurodegenerative diseases such as Alzheimer's.

From Science Daily ● May 24, 2026

"We found that disease-associated genetic variants often work by altering DNA methylation in specific immune cell types," says co-first author Wubin Ding, PhD, a postdoctoral fellow in Ecker's lab.

From Science Daily ● Feb. 11, 2026

The team found that this silencing occurs through DNA methylation, a natural process that adds chemical tags to DNA, turning the gene off.

From Science Daily ● Nov. 5, 2025

Johnson routinely measures everything from his blood sugar levels to his DNA methylation: a natural genetic change that can be used to estimate the pace of aging.

From Slate ● May 28, 2025

Evaluating the merits of these awards would require a deep understanding of dozens of scientific fields, from gravitational waves to DNA methylation.

From Salon ● Mar. 1, 2025

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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023