Number of CO events per chromatid deduced from the genotype of an F2 plant. When an F2 plant displays two COs, either the extremities of both chromosomes are homozygous, and the COs are on one chromatid or both, or the extremities are heterozygous and there is ambiguity between one event on each chromatid or two events on the same chromatid. A similar approach has been used to analyse F2 plants that displays three COs. When an F2 plant displays more than three COs, the recombination history cannot be inferred from the genotype. In the columns “COs/chromatid,” the numbers in parentheses represent the number of plants in each category. (Light gray box) plants used in the interference analysis. (Dark gray box) plants containing a chromatid with two COs but that could not be used in the interference analysis.
