Behaviour of Flanking Markers in Allelic Crosses

The principles of analysis of the distributions of flanking markers amongst prototrophic recombinants arising from allelic auxotrophic differences are discussed. Considerable variations occur in the parameters which may be measured and also in the degree of agreement of criteria used to place allelic differences in order in fine structure maps. At least some of these variations appear likely to depend upon genetic differences affecting the mechanisms which result in genetic recombination and the mechanisms which control their activity. An approach to a quantitative theory of the distribution of flanking markers is suggested.