Question

If an organism that is homozygous recessive for a trait is crossed with a heterozygote, what is the chance of getting a homozygous recessive phenotype in the first generation?

A. 0
B. 0.25
C. 0.5
D. 1

Answer 1

The answer is C. We suppose the gene type of homozygous recessive is "aa", and the heterozygote is "Aa", then the first generation will be "Aa" or "aa" which are equal chance. So the chance of getting a homozygous recessive phenotype is 0.5.