title: The relationship between chromatid interference and the mapping function.
abstract: A formula for a general mapping function involving only the number of chiasmata between two points on the chromosome and the average excess of four-stranded double exchanges over two-stranded double exchanges is derived. A formula is also given for deriving the proportion of three-stranded double exchanges after any given number of chiasmata; this is related to mapping for linkage with the centromere. It is shown that this proportion tends to a limit of 2/3 after a large number of chiasmata, whether or not chromatid interference is operating.
mesh_terms: D002842:Chromatids / Q000502:physiology*; D002874:Chromosome Mapping; D003434:Crossing Over, Genetic; D008954:Models, Biological; D013223:Statistics as Topic