Answer:
13
Step-by-step explanation:
Short tandem repeats (STRs), also known as microsatellites, are short DNA sequences containing core repeat units of between 2-7 nucleotides (nts) which are tandemly repeated. The STR analysis is commonly used in molecular biology laboratories in order to identify DNA samples by comparing STR loci between samples. For example, the Federal Bureau of Investigation (FBI) uses 13 STR loci for the identification of individuals in the USA. It is important to note that these 13 loci are independently assorted (i.e. they are not linked), and thereby their combined use results in a very low ("nearly zero") false-positive identification rate.