Question

Assertion (A) : Gene pairs present on the same chromosome may be tightly linked or loosely linked. Reason (R) : Frequency of recombination between gene pairs on different chromosomes as a measure of the distance between genes can be used for 'mapping' their position on the chromosomes.

Assertion (A) : When the two genes in a dihybrid cross are situated on the same chromosome, the proportion of parental gene combinations is much higher than non-parental type. Reason (R) : Higher parental gene combinations can be attributed to crossing over between two genes.