An inferred chiasma map of Drosophila melanogaster.
The chiasma map of D. melanogaster is inferred from the genetic map, giving correspondences between physical and genetic locations. Crossing-over is reduced near the centromere and telomeres. If chiasmata occur preferentially near the telomere they must be distal to genetic loci. A precept of Bridges and Morgan is discussed, which Drosophila genetics neglected but chromosome mapping in other organisms should follow.
D000818:Animals; D002874:Chromosome Mapping; D002875:Chromosomes; D003434:Crossing Over, Genetic; D004331:Drosophila melanogaster; D008433:Mathematics