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Automated short tandem repeat (STR) analysis in forensic casework — a strategy for the future
Author(s) -
Gill Peter,
Kimpton Colin P.,
Urquhart Andrew,
Oldroyd Nicola,
Millican Emma S.,
Watson Stephanie K.,
Downes Terry J.
Publication year - 1995
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.11501601257
Subject(s) - microsatellite , locus (genetics) , genetics , biology , str analysis , polymerase chain reaction , allele , tandem repeat , dna , computational biology , gene , genome
Short tandem repeat (STR) loci are routinely analysed for forensic purposes in the UK. Because small regions of DNa are amplified, successful results are more likely to be obtained from highly degraded material where the DNA fragment length may be < 500 bp. The method is superceeding conventional analysis with single locus probes (SLPs). Dimeric STR loci display stutter artefacts, hence STRs used in casework are restricted to tri or tetrameric loci. Some STRs are complex repeats and have more alleles than simple repeats – for example the locus D21S11 has 21 alleles which differ in size by 2 bp because of the presence/absence of a hexanucleotide within the block of tetrameric repeats. These loci are of great potential interest because they combine increased discriminating power with reduced potential to stutter. Multiplexing 4 different loci with different dye labelled primers ( i.e. carrying out polymerase chain reaction of 4 loci simulataneously) using the ABD 373 A automated sequencer enables a large numbers of samples to be processed. In addition data aquisition and manipulation is automated so that minimum postelectrophoresis operator input is required. It is our aim to develop a system equivalent in power to that of 4 single locus probes. To achieve this we have developed an octoplex system consisting of 7 loci and a sex test (amelogenin locus) which has a probability of chance of association of 10 −9 ; the power of this system is equivalent to that achieved by 4 conventional SLPs.