Question

A researcher was performing a cross between two individuals of a species to verify Mendel’s law of independent assortment experimentally, but every time he performs the experiment, he finds that some characters do not assort independently, this is due to

• A. the crossing over between the genes
• B. the linkage between the genes
• C. the dominance of one trait over the other
• D. the recombination between the genes

Answer 1

The correct option is B the linkage between the genes

Genes that are sufficiently close together on a chromosome will tend to stay together during inheritance. Linked genes are those genes that do not show independent assortment but remain together as they are present in the same chromosome. If there is no occasional crossover, then there is a tendency to maintain the parental gene combination.

Crossing over acts inversely to linkage. If there is a cross over between two genes then there is less chance to maintain the parental genotype in the gamete and this leads to recombination. Factors or alleles assort independently when they are present on the separate chromosomes or distantly located.

Mendel’s crosses yielded the traits by assorting independently while forming the gametes. But here in the experiments of the researcher, the traits do not assort independently, as they are tightly linked to each other and gets coupled or linked with other alleles of the same chromosome.