Abstract
During meiosis DNA undergoes recombination through crossing over within homologous chromosomes to produce genetic variability. It has been previously shown that a crossover at any given point interferes (crossover interference) with the occurrence of crossovers at nearby locations on the same chromosome. How interference occurs is unknown. Crossover interference could be induced by a release of tension in the chromosome ("stress model") or by some unknown system that counts a specific number of genetic distances away from the point of crossover before allowing another crossover ("counting model"). Studying the effects of a crossover between nonhomologous chromosomes will give light to the necessity for the participation of homologues in crossing over and interference. Preliminary data show that under conditions in which an ectopic recombination event is occurring, interference is nonexistent, indicating that both homologues of a chromosome must be present for crossing over and interference to occur, a necessity in proper segregation and propagation of genetic diversity.