DNA STR Typing

Short Tandem Repeats In mammalian genomes have tandem repeats ……ATTCGATTCGATTCG…… There are currently over 10,000 published STR sequences in the human genome. These are usually junk DNA. Therefore the variations between individuals are significant. For example: One particular STR may have form (gata)n, n may be from 10 to 20 across different individuals.

D7S280 D7S280 is one STR site of the 13 core STR sites in the CODIS standard. By designing a pair of primers, we can amplify the region and measure the length using gel electrophoresis. By using multiple STR sites, we can determine an individual with high confidence. 1 aatttttgta ttttttttag agacggggtt tcaccatgtt ggtcaggctg actatggagt 61 tattttaagg ttaatatata taaagggtat gatagaacac ttgtcatagt ttagaacgaa 121 ctaacgatag atagatagat agatagatag atagatagat agatagatag atagacagat 181 tgatagtttt tttttatctc actaaatagt ctatagtaaa catttaatta ccaatatttg 241 gtgcaattct gtcaatgagg ataaatgtgg aatcgttata attcttaaga atatatattc 301 cctctgagtt tttgatacct cagattttaa ggcc

Combined DNA index system

Promega’s product

Multiplex PCR Primers are designed to ensure that different sites fall in non-overlapping regions. Primers in different groups are labeled with different fluorescents.

As of May 2007, 177,870 forensic profiles and 4,582,516 offender profiles have been accumulated in CODIS, making it the largest DNA databank in the world surpassing the United Kingdom's National DNA Database, which consisted of an estimated 3,976,090 profiles as of June 2007. As of the same date, CODIS has produced over 49,400 matches to requests, assisting in more than 50,343 investigations