Cats and catmint, dogs and dog roses, man and mangroves are connected in more than name. Plants and animals have many biological processes in common; for example, RNA interference (RNAi) – a way of inactivating genes. It most likely evolved to stop foreign genes – for example from viruses – pervading the genome. A clue to its existence came when an attempt to create a deeper-hued petunia (pictured) by putting a pigment-producing gene sequence into its cells, instead engendered white flowers. Andrew Fire – born on this day in 1959 – and Craig Mello, working with C. elegans worm, discovered why in 1998. The petunia pigment gene was ‘silenced’, because the colour-enhancing sequence was in the form of double-stranded RNA – mimicking certain naturally encountered foreign sequences. This activated RNAi which diced the gene’s message, muting it. Understanding RNAi has revolutionised biomedical research. Today, biologists worldwide use it to discover the consequences of turning genes off.
Written by Lindsey Goff
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