CNN
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This year’s Nobel Prize in Physiology or Medicine was awarded to Victor Ambros and Gary Ruvkun for their work discovering microRNA, a fundamental principle that controls the regulation of gene activity.

The Nobel Prize Committee announced the prestigious award, considered the pinnacle of scientific achievement, on Monday in Sweden.

It praised the “groundbreaking discovery” by American biologists, which, according to the committee, “revealed a completely new dimension of gene regulation.”

Ambros, a professor of natural sciences at the University of Massachusetts Medical School, conducted the research that earned him the prize at Harvard University. Ruvkun conducted his research at Massachusetts General Hospital and is a professor of genetics at Harvard Medical School.

In their early work, the pair examined the genetic makeup of a tiny, 1-millimeter-long roundworm, C. elegans. Despite its small size, this worm has many specialized cell types, such as nerve and muscle cells, that are also found in larger, more complex animals, making it a useful model for studying tissue development and maturation in multicellular organisms.

“The information stored in our chromosomes can be compared to an instruction manual for all the cells in our body. Every cell contains the same chromosomes, so every cell contains exactly the same set of genes and exactly the same set of instructions,” the committee said in a statement detailing the duo’s work.

And yet different cell types – such as muscle and nerve cells – have different properties. The two biologists have spent their careers studying how these differences arise.

“The answer lies in gene regulation, which allows each cell to select only the relevant instructions. This ensures that only the correct set of genes is active in each cell type,” the committee said.

Ambros and Ruvkun discovered microRNA, a new class of tiny RNA molecules (nucleic acids essential for most biological functions) that are essential for gene regulation.

The discovery helped reveal that the human genome encodes over 1,000 microRNAs.

Last year, the prize was awarded to Katalin Karikó and Drew Weissman for their work on MRNA vaccines, a crucial tool to curb the spread of Covid-19.

The prize is worth 11 million Swedish crowns (US$1 million).