Final answer:
Crossover interference refers to the decrease in the likelihood of additional crossovers occurring in a region where a crossover has already occurred, influencing the number of recombinant offspring and affecting genetic mapping.
Step-by-step explanation:
The degree to which one crossover interferes with additional crossovers in the same region of a chromosome is known as crossover interference or simply, interference. This concept is crucial in understanding genetic linkage and recombination. Crossover interference has an important effect on the genetic mapping of chromosomes; as one crossover can reduce the probability of subsequent crossovers in nearby regions, affecting the observed number of recombinants. When two genes are closer together on a chromosome, there is a lower chance for a crossover to occur between them, meaning alleles of these genes are more likely to be inherited together.
However, as the distance between two genes increases, so does the likelihood of crossovers occurring between them, leading to a higher proportion of recombinant, or nonparental, gametes. The relationship between the frequency of crossover and genetic distance is quantified in units called centimorgans (cM).