1 Why is crossing over between two genes on the same chromos

1. Why is crossing over between two genes on the same chromosome from 0% to 50%, and not higher?

2. Why is linkage between two genes on the same chromosome from 50% to 100%, and not lower?

Solution

They are so far apart on one chromosome that there is
a 100% likelihood of a crossover occurring between them
- 50% recombination frequency because only half the chromatids are involved in a crossover event (except rare cases)

Because crossing over occurs at the 4-strand stage of the cell cycle (that is, after S phase) so that each single crossover involves only 2 of the 4 chromatids. So 50% parental chromatids are produced and 50% crossover chromatids are produced.

Genetic linkage: genes located on same chromosome may be inherited together in genetic crosses