Question

If a homozygous dominant parent and a heterozygous parent are crossed, what percentage of the offspring are expected to be homozygous recessive?

Answer 1

0%. The types of offspring could be QQ ,QQ ,Qq and Qq. Homozygous recessive is qq and that is not an option.

Answer 2

Answer: The correct answer is-

The percentage of the offspring that are expected to be homozygous recessive (qq) is 0 %.

As per the information given in the question, the genotypes of parent are-

Homozygous dominant ( QQ) and a heterozygous ( Qq).

Gametes produced are-  QQ parent will produce Q and Q gametes while Qq will produce Q ands q allele.

A dominant allele ( represented by capital letter such as Q) always masks the expression of recessive allele ( represented by small letter such as q)

Homozygous genotye has same alleles whereas heterozygous genotype contains different alleles ( one dominant and one recessive such as Qq).

When the parents are crossed, they will produce 50 % QQ and 50% Qq offsrping but no qq offspring will be produced

Refer punett square.