MathBench > Probability

Linked Genes and Recombination
Advanced Punnett

But how often does cross-over occur?

So far we have been assuming that crossover occurs in 10% of meiosis, but this was just a convenient number, not a general rule. How often cross-over actually occurs depends on how far apart the two genes are on the chromosome.

Why? Crossover is a random process. In other words, where the chromosome gets split is random. Therefore, alleles that are farther apart are more likely to get broken apart: