• The term interference was coined by Muller which refers to the tendency of one crossover to reduce the chance of another crossover in its adjacent region. Interference is affected by gene distance on the chromosome.
• Lesser the gene distance greater is the interference and vice versa.
• Generally, it is observed that crossing over in one region of chromosome may check the crossing over in the second region.
• Sometimes, presence of recombination in one region enhances the chance of recombination in another adjacent region.
• This is termed as negative interference. This type of situation has been observed in some lower organisms, viz., Aspergillus and bacteriophages.

Coefficient of interference is estimated as follows:

Coefficient of interference (%) = 1 – Coefficient of coincidence x 100