Question

Orange coat color of cats is due to an X-linked allele (Xo) that is codominant with the allele for black (X+). When genotypes at the orange locus were determined for a sample of cats in Minneapolis and St. Paul, Minnesota, the following data were obtained:XoXo females: 11XoX+ females: 70X+X+females: 94XoY males: 36X+Y males: 112Calculate the frequency of the XO and X+ alleles (Y does not contribute) for this population.

Answer 1

Answer:

The X₀ frequency  is 0.26

The X+ frequency  is 0.74

Explanation:

Available data:

• The orange coat color of cats is due to an X-linked allele (Xo)

• X₀ is codominant with the allele for black X+

• X₀X₀    11

• X₀X+    70

• X+X+    94

• X+ Y    112

• X₀ Y     36

To alculate the frequency of the X₀ and X+ alleles you need to sum the times it appears X₀ and the times it appears X+ alleles in the population. These sums will give you the number of alleles. As you need to calculate the frequency of these alleles, you will have to divide each number by the total number of both alleles together. This is:

• X₀ = 2 x (X₀X₀) + (X₀X+) + (X₀Y) = (2 x 11) + 70 + 36 = 128

• X+ = 2 x (X+X+) + (XoX+) + (X+Y) = (2 x 94) +70+ 112 = 370

The total number of alleles in the population is 128 + 370 = 498

To talculate the allele frequencies, f, you need to divide each allele number by the total allele number:

f (X₀) = 128/498 = 0.26

f (X+) = 370/498 = 0.74