A man and a woman that are both heterozygous for the allele for brown eyes (blue

Question

A man and a woman that are both heterozygous for the allele for brown eyes (blue eyes are the recessive trait) are planning on having children.

a. Assuming a sex ratio of 1:1, what is the expected distribution of the sexes if they have seven children, i.e., what are the male/female frequencies for all possible seven-child families? Show your work. Answer:

b. Suppose they have three children with blue eyes and four with brown eyes. Are the observed progeny numbers consistent with Mendelian expectations? State your hypothesis, predictions, calculations, P value, and conclusion.

Explanation / Answer

Father Mother

Bb Bb

children born- BB-25% with brown eyes

Bb- 50% with brown eyes

bb-25% with blue eyes

Thus only one child will have blue eyes rest all the 6 will have brown eyes.

b.These observations are not consistent with Mendelian principles as 25% should be with blue eyes.

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