| Length polymorphism analysis of DNA fragments is the conventional method used in the human identification fields. Structural polymorphisms of STR alleles have the same base pair length, but differ in the composition of the repeats in the variable regions, and their examination can provide a second level of discrimination in human identity applications. This study revealed seven structural polymorphisms in allele 30 at STR locus D21S11 from African American and Caucasian individuals in North America, including three which have never been observed before. Statistical analysis of the power of discrimination, heterozygosity, and the power of exclusion, useful in forensic and paternity analysis, all increased when the seven variants characterized in this study were taken into account. The study underscored the advantages of characterizing STR structural polymorphisms over length polymorphism and explores the potential applications of this added discriminatory power. |
