Perkins 1 and Whitehouse 2 have shown how chromosome centromeres can be mapped by the analysis of unordered tetrads of spores (or gametes), provided segregation is occurring at three unlinked loci.

IN many fungi, such as most of the Ascomycetes and Ustilaginales, the products of meiosis are arranged regularly in a linear order, and by examining them or by isolating them in order, it is possible ...