Sea lampreys shed genes
A new study in the journal Current Biology shows how sea lampreys get round the problem of controlling when and where to switch genes on and off - they simply get rid of them. Sea lampreys are simple, parasitic eel-like vertebrates, which are considered to be a pest in some parts of the world. The researchers, led by Chris Amemiya at the Benaroya Research Institute in the US, discovered that lampreys shed more than a thousand genes from their cells during development - around a fifth of their whole genome. The only cells to keep all their genes intact are primordial germ cells, which go on to make eggs and sperm.
Looking closer, the scientists found that many of the lost genes are involved in pluripotency - the key characteristic of stem cells. In higher species, these genes are only needed during development or in stem cells, and have to be switched off. But they can be reactivated in diseases such as cancer. By simply getting rid of these risky genes, the sea lampreys sidestep this problem altogether. The researchers believe their findings will help to shed light on how gene regulation has changed through evolution, both in health and in disease.