Question

In a testcross involving $F_1$ dihybrid flies,more parental-type offspring were produced than the recombinant-type offspring. This indicates.

• A. chromosomes failed to separate during meiosis
• B. the two genes are linked and present on the same chromosome
• C. both of the characters are controlled by more than one gene
• D. the two genes are located on two different chromosomes

Answer 1

The correct option is B the two genes are linked and present on the same chromosome

Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two genetic markers that are physically near to each other are unlikely to be separated onto different chromatids during chromosomal crossover, and are therefore said to be more linked than markers that are far apart. In other words, the nearer two genes are on a chromosome, the lower the chance of recombination between them, and the more likely they are to be inherited together. Markers on different chromosomes are perfectly unlinked.

So the correct option is 'the two genes are linked and present on the same chromosome'.