Practice question

Complete interference describes extreme inhibition where one crossover totally prevents second crossover in adjacent interval, so observed double crossover count zero in genetic data. Consequently coefficient coincidence C = 0 / expected = 0 and interference I =1-0 =1 indicating 100 percent interference. Biologically ensures each bivalent obtains at least one obligate chiasma but not excessive nearby exchanges that might cause nondisjunction or chromosome entanglement. Phenomenon common over short intervals less than about 10 centimorgans in Drosophila, mammals, enhancing proper segregation fidelity.