Human gene 'cures' colour-blind mice

Stephen Withers
Monday, 26 March 2007 05:38

Science - Biology

Mice normally see a limited range of colours - similar to the palette available to people with red-green colour blindness - but researchers have found that inserting a relevant human gene gives them much broader colour vision.

Most mammals only have photoreceptors that respond to blue and green light, while primates - including humans - also have them for red light. One advantage is that this allows them to distinguish between ripe and unripe fruit.

A team led by Gerald Jacobs, research professor in the Department of Psychology and the Neuroscience Research Institute at the University of California Santa Barbara (UCSB), and Jeremy Nathans, professor of molecular biology and genetics at The Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute researcher, compared the colour vision of normal mice with others that were genetically engineered to have green and red photoreceptors.

The mice were presented with three panels displaying coloured light, and rewarded with a drop of soymilk when they correctly identified the odd one out. The genetically engineered mice were able to discriminate colours that normal mice could not, choosing the correct panel 80 percent of the time compared with one third of the time for the normal mice.

The significance of this result is that the mice's brains were immediately able to handle the new information. "Our observation that the mouse brain can use this information to make spectral discriminations implies that alterations in receptor genes might be of immediate selective value not only because they expand the range or types of stimuli that can be detected but also because they permit a plastic nervous system to discriminate between new and existing stimuli," the team reported in an article published last week in Science.