Figure 6.7 PCR can be used to type short tandem repeat polymorphisms (STRPs).

The example illustrates typing of a (CA)/(TG) dinucleotide repeat polymorphism which has three alleles as a result of variation in the number of CA repeats. On the autoradiograph each allele is represented by a major upper band and two minor 'shadow bands'. Individuals A and B have genotypes (in brackets) as follows: A (1,3); B (2,2).

from Strachan and Read, Human Molecular Genetics 2, Wiley-Liss, New York, 1999 (on reserve)