Practice question

Coefficient coincidence measures strength crossover interference experimentally during meiosis by comparing observed versus expected double crossovers. Expected double crossover frequency calculated assuming independence as product of observed recombination fractions for adjacent intervals, based on basic probability theory assuming no chromatid interference. Observed DCO frequency obtained by directly counting double recombinant phenotypes in large progeny sample. Ratio observed divided by expected defines C. If C =1 crossovers independent, no interference operating. If C <1 positive interference observed DCO fewer than expected, indicating inhibition of nearby second exchange.