Two different gametes are formed but the A gene is paired with the b gene. It rarely is found with the B gene and similarly, a & b are hardly ever found in the same gamete because they are not linked. However, on occasion, some phenotypes appear to suggest that indeed A and B do join with the reciprocal a and b alleles linked. The process by which this occurs is called crossing over and by flipping to the next card, the mechanism of the process can be studied.