Mutant mice become ‘super sniffers’

Its stripy back makes it one of the most recognisable of rodents – but until now it has been unclear exactly how the chipmunk earned its stripes.

Now, scientists have found the evolutionary gene change responsible for the distinctive markings of both the chipmunk and an African mouse, according to BBC.

The gene normally makes the bellies of many rodents light in colour.

The stripes may have helped the animals hide from daytime predators with keen eye sight, such as birds, they say.

Prof Hopi Hoekstra, of Harvard University, US, who led the research, said: “What these two rodents have in common is that they are both diurnal [active during daylight], when one could imagine stripes could be more valuable than if they were nocturnal.

“It is notable that of the rodents that are striped, most are diurnal – again consistent with them being important for evading visual predators (for example, raptors and mammalian carnivores).”

The African striped mouse has a pattern of two dark-light-dark stripes on its back.

The dark and light stripes can be seen as soon as the mouse pups are born.

Research shows a gene change causes skin cells called melanocytes to stop making dark pigment in a particular area of the mouse’s back, causing a white stripe.

A similar thing happens in the chipmunk.

In some other animals, white patches are caused by a lack of melanocytes in a particular area of the body – such as the blaze on the nose of a horse or a white bib on a cat.

Scientists think they probably evolved their stripes independently.

H.Z