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Definition of methylation
: the introduction of a methyl radical into a substance
The methylation of metals (that is, the substitution of a metal atom for the hydrogen atom of the hydroxyl group of a methyl alcohol molecule) can result in the metal's becoming volatile.— Corale L. Brierley especially : dna methylation As cells begin to specialize into adult tissues, methylation seems to inactivate genes that are no longer needed. — John Travis
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Time Traveler for methylation
The first known use of methylation was in 1855
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