From Cassandra Willyard at Nature:
At the time, biologists were getting excited about the epigenome — the broad array of chemical marks that decorate DNA and its protein scaffold. These marks act like a chemical notation, telling the cell which genes to express and which to keep silent. As such, the epigenome helps to explain how cells with identical DNA can develop into the multitude of specialized types that make up different tissues. The marks help cells in the heart, for example, maintain their identity and not turn into neurons or fat cells. Misplaced epigenetic marks are often found in cancerous cells.
Why didn’t it happen sooner?:
The governing rule of molecular biology – the central dogma – holds that information flows from DNA to messenger RNA to protein. Many scientists therefore viewed mRNA as little more than a courier, carrying the genetic information encoded in a cell’s nucleus to the protein factories in the cytoplasm. That’s one reason why few researchers paid much attention to the modifications made to mRNA.
They were Darwinists. Simlicity was their Central Dogma, remember?
Oh, by the way, this is what the story sounds like now:
Over the past few years, researchers have identified some of the machinery involved in regulating these marks. Each requires a writer to place it, an eraser to remove it and a reader to interpret it (see ‘Reading, writing and regulation’). As the identities of these proteins emerged, scientists have come to understand that m6A affects not only RNA splicing, but also translation and RNA stability. More.
It all sounds like something that just sort of happened, right?
See also: Central Dogma: Missing, and presumed dead
and
Epigenetic change: Lamarck, wake up, you’re wanted in the conference room!
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