Linkage, recombination and mapping

So far we have seen that some traits of the laboratory mouse exhibit segregation in conformity with Mendel’s principle of segregation of alleles and that some sets of two traits exhibit assortment in conformity with Mendel’s principle of random assortment of non-alleles. In this chapter, we shall deal with an experiment in which the first principle holds but the second does not. Instead of random or independent assortment of non-alleles, we shall be led to infer, as many others have done since 1910, when Morgan perceived the phenomenon, that there can be non-random or dependent assortment of non-alleles. This phenomenon is called genetic linkage or, simply, linkage.