Question

In dragons, straight tails require the presence of either or both of two dominant alleles, Z and T. Individuals homozygous for both recessive alleles have zigzag tails. The two genes are on the same chromosome and recombine with a frequency of 24 percent. From the cross ZT/zt X ZT/zt, what is the expected frequency of individuals with zigzag tail in the progeny?

a) 24%
b) 48%
c) 72%
d) 96%

Answer 1

The expected frequency of individuals with zigzag tails in the progeny is 25%.

Step-by-step explanation:

In dragons, straight tails require the presence of either or both of two dominant alleles, Z and T. Individuals homozygous for both recessive alleles have zigzag tails. The two genes are on the same chromosome and recombine with a frequency of 24 percent. From the cross ZT/zt X ZT/zt, the expected frequency of individuals with zigzag tail in the progeny can be determined using the Punnett square method.

When we cross ZT/zt X ZT/zt, we get the following genotypes in the progeny:

ZT/ZT, ZT/zt, ZT/zt, zt/zt

Out of these, only the genotype zt/zt represents individuals with zigzag tails. Therefore, the expected frequency of individuals with zigzag tails in the progeny is 1 out of 4 or 25%.