Question

1.

Wool color in sheep is under the control of an autosomal gene which segregates two alleles: B,confers white wool, while the recessive allele b specifies black wool. A population of sheep under Hardy-Weinberg equilibrium was observed: Of 325 individuals, 194 have white wool and 131 have black wool.

.

What is the frequency of the B allele?

b.

How many of the 194 white sheep are expected to be heterozygous?

2. Cat coat color is controlled by an X-linked gene with two alleles: X^B= Black and X^O = Orange. A population of cats in Tampa was found to consist of the following phenotypes:

	Black	Orange	Calico	Totals
Males	311	42	0	353
Females	277	7	54	338

Calculate the allelic frequency using all of the available information.

Answer 1

B represents dominant character, that codes for white wool and have 194 individuals.

b represents recessive character, that codes for black wool and have 131 individuals.

Let allelic frequency for B is represented as p in homozygous condition.

Therefore, Frequency for white wool = No.of individuals / Total no.of individuals

= 194 / 325 = 0.5969

Now, this means, BB = p² = 0.5969

Therefore, p =

Thus, p = 0.7726

As we know, p + q = 1

0.7726 + q = 1

Thus, q = 0.2274

Frequency in Heretozygous condition = 2pq

= 2 X 0.7726 X 0.2274

= 0.3513

Now. according to question, we need to find no. of individuals who are heterozygotes among 194 white wool individuals, which is a dominant character.

Therefore, 194 X 0.3513 = 68.1522

Approx = 68 heterozygous individuals for wite wool among 194 total white wool individuals.