Color blindness is an X-linked recessive trait. Suppose that in a random sample there are fB normal females, fb color-blind females, mB normal males, and mb color-blind males. If n = 2fB + 2fb +mB +mb is the number of genes in the sample, then show that under HardyWeinberg equilibrium the maximum likelihood estimate of the frequency of the color-blindness allele is pˆb = −mB + m2 B + 4n(mb + 2fb)

2n .

Compute the estimate ˆpb = .0772 for the data fB = 9032, fb = 40, mB = 8324, and mb = 725.

These data represent an amalgamation of cases from two distinct forms of color blindness [4]. Protanopia, or red blindness, is determined by one X-linked locus, and deuteranopia, or green blindness, by a different X-linked locus.