Re: How are green eyes inherited?

April 27, 2001

Dear Sarah,

We cannot think in terms of "green eyes (being) the result of racial 
mixing.  Particular physical traits are understood by modern biologists as 
represented by "clines." or gradual variation in the preponderance of a 
trait over geographical space.  In regard to eye color, there seems to be a 
complex phenotypical and genotypical interaction in the resultant color.  
Different amounts of pigmentation seem to be advantageous in evolutionary 
selection in different environments.  However, eye pigmentation variation 
is apparently quite complex and offers no simple gradation as is found with 
some other traits.

Dr. Smerken