Final answer:
Genetic distance can be estimated by measuring recombination frequency, which correlates to how far apart genes are on a chromosome, expressed in centimorgans.
Step-by-step explanation:
Genetic distance (crossover frequency) can be estimated by measuring the recombination frequency, which is observed as the number of nonparental genotypes among offspring. The higher the recombination frequency, the further apart the genes are on the chromosome. This frequency is correlated with map distances in centimorgans (cM), where 1% recombination frequency is equivalent to 1 cM. For example, if the recombination frequency between two genes is found to be 17%, it implies that the genetic distance between them is 17 cM. This also indicates that, on average, 17 percent of the offspring will display recombination of these two genes.