Fact of the Day .CA

Researchers have successfully found a way to restore red-green vision to colour blind adult Spider Monkeys.  The monkeys were trained to touch coloured dots with their head on a touch screen.  The screen was filled with grey dots of varying sizes and a select cluster of the dots were coloured; the select cluster of dots varied for each session.  This was similar to the images used to determine colour blindness in humans: a circle of dots with select dots being coloured differently to creat the shape of numbers (see one here).  When done correctly the monkeys were given grape juice as a reward.  Some of the monkeys had normal colour vision while others had colour blindness.  The colour blind monkeys were unable to detect the red or green coloured dots among the grey ones.  They were not rewarded on these occasions and were said to have gotten frustrated and would even shake the screen.  Two of the monkeys with colour blindness were given gene therapy via an altered virus injected behind the retina of the eye.  The gene that the virus inserted was that for the red pigments found in cone cells (which detect colour) of the eye.  After 20 weeks the two monkeys were capable of seeing red and green; as was shown by their increased ability to correctly identify the coloured dots.  This could have great implications for humans; colour blindness is the most common genetic disorder for humans.  It is also interesting because it has been believed that the adult human brain is unable to undergo new changes.  This study showed that adult monkeys were able to take in the new gene to alter the activation of cone cells in the eye, suggesting that the brain is capable of making alterations during adulthood.

Sources:

http://news.nationalgeographic.com/news/2009/09/090916-color-blind-gene-monkeys.html

http://www.nature.com/news/2009/090916/full/news.2009.921.html