Describe how the relative numbers of PDS and NPDs can be used to establish linkage.

Linkage may be defined as the transmission of chromosome to the next generation that are located on same chromosome. Linkage results in the formation of recombination progeny.

PDS (parental ditypes) and non parental diypes can be used to find linkage in the Neurospora and other organism Parental ditypes has the genotype same as parental genotype whereas non parental ditypes contains recombinant progeny. If the ratio and arrangement of PDS and NPDs is 2:4:2 or 2:2:2:2. This means linkage is present between the gene and centromere of an organism.