Nathans, J. 1989. The genes for color vision. American Scientis
t. February 1989.
See also for review:
Zhang, J. 2003. Evolution by gene duplication: an update. Trends
in Ecol and Evol. 18:292-298.
Have the students test themselves for colorblindness. There are several
websites with color-blindness tests available.
You can also find a copy of Ishihara's Tests for Colour Blindness in most
Have students calculate frequency of colorblindness in the class - what
% of men and what % of women are red/green colorblind?
Do your class results conform to published rates?