Women see crimson and burgundy, men see red

Research carried out at Arizona State University reveals that the gene that allows people to see red has a surprising number of variations. As this gene is on the X chromosome, women have two copies whilst men have only one. The research team believes this may cause a difference between the way men and women see red.

The researchers analysed the DNA of 236 men from around the world and found 85 different variations in a gene called OPN1LW. Most genes have around a third of this number of variations. OPN1LW is the gene for the pigment that allows the eye to see red, so the researchers think that variations in the gene may lead to differences in the shades of red seen by the eye. If women have two different variations, one on each X chromosome, they may be able to sense a more shades of red.

The research, to be published in the September edition of the American Journal of Human Genetics, steers away from previous research in the area, which has tended to focus on colour-blindness. Pieces of DNA are often swapped between the gene for seeing red and the gene for seeing green, resulting in the inability to distinguish between red and green.

Dr Brian Verrelli, leader of the research team, suggested that the gene variations may have existed for some time. He said, 'if it has been around this long, this suggests that it was beneficial and kept in the population by natural selection. Females may have historically been better at gathering fruits and other food items because of their better colour discrimination in the red range'. However, he accepted that 'today it's not really that important'.