Final answer:
More double-crossover events than expected occurring, which is indicated as a negative number, relates to negative interference.
Step-by-step explanation:
More double-crossover events than expected occurring, which is indicated as a negative number, relates to negative interference. Interference is a measure of how crossovers between genes on a chromosome affect each other. Negative interference means that the occurrence of one double-crossover event reduces the likelihood of another double-crossover event happening nearby.