Crossing over is a relatively rare event although it is a very real part of DNA metabolism and an important mechanism for changing gene associations. The process can occur anywhere along the length of the chromosome although localized regions display greater or lesser tendencies to engage in the process. Clearly, the closer two genes lie on the chromosome, the less frequently they will cross over since where the break in the DNA occurs appears to be a randomized process. This method permits geneticists to map the location of different genes. The next section of the stack presents you with a mapping exercise. Click on the appropriate button.
