Question

In what way is linkage in opposition to Mendel’s law of independent assortment? Explain.

Answer 1

Linkage opposes Mendel’s law of independent assortment because it involves genes located close together on the same chromosome that tend to be inherited together rather than assorting independently. Mendel’s law states that gene pairs on different chromosomes assort independently during gamete formation, leading to a 9:3:3:1 phenotypic ratio in dihybrid crosses. However, linked genes do not follow this pattern because they do not segregate independently; instead, they show parental gene combinations more frequently and reduce the expected recombinant types. This was not observed by Mendel because the genes he studied were on different chromosomes (unlinked). Linkage thus represents an exception to the law of independent assortment and results from physical proximity of genes on the same chromosome, affecting their inheritance during meiosis, unless crossing over occurs to recombine them.