Question

A fruit fly of genotype BRbr is testcrossed to brbr. In 16% of the meioses, there is one chiasma between genes. What proportion of the progeny will be Brbr?

Answer 1

The proportion of the progeny that will be Brbr is 50%.

Step-by-step explanation:

In this case, the fruit fly has the genotype BRbr, which means it has one dominant allele (BR) and one recessive allele (br) for eye color. It is testcrossed with a fruit fly that is homozygous recessive for eye color (brbr). The offspring will inherit one allele from each parent. Since the parent with genotype BRbr only has one dominant allele, there is only a 50% chance that the offspring will inherit the dominant allele (BR). Therefore, the proportion of progeny that will be Brbr is 50%.