ABSTRACT
An STR is a region of human DNA containing an array of tandem repeats. Arrays range from only a few to about a hundred repeated units. A repeat unit can be 2 to 6 base pairs (bp) long. STRs are also called microsatellites or simple sequence repeats. The number of repeat units of STR loci can vary greatly among the population. The most commonly used STR loci are 100 to 500 bp in length-shorter than the smallest VNTRs (up to 1000 bp). STR loci have many advantages due to the small size of the alleles:
• STR loci are applicable for PCR amplification. • STR profiling performs better than VNTR profiling for degraded DNA
samples. • Preferential amplification is reduced at STR loci compared to VNTR
loci using AFLP. • Better electrophoretic resolution of DNA fragments is achieved than
VNTR profiling. • STR loci are applicable for multiplexing amplification. • STR profiling, As with VNTR profiling, is capable of handling inter-
pretation of mixed DNA profiles from multiple contributors.
