Genetic Controls of Allelic Recombination in Neurospora

Abstract

MAPS of the fine structure of genes are intended to exhibit the positions relative to one another, and to other genetic markers, of the sites of difference from the normal of a series of allelic mutants. Commonly, in their construction, most reliance is placed on the frequencies of prototrophs observed to arise in repulsion phase crosses between pairs of alleles. It is assumed that the order of the sites may be deduced from these values of prototroph frequency by application of the additivity rule. This is that any pair, m¹ and m², shows a value which is approximately the sum or difference of the values shown by each of these alleles with a third one, m³. In practice any substantial body of data shows ambiguities and inconsistencies.