Mini-midi-mito: adapting the amplification and sequencing strategy of mtDNA to the degradation state of crime scene samples.
The degradation state of some biological traces recovered from the crime scene requires the amplification of very short fragments to attain a useful mitochondrial (mt)DNA sequence. We have previously introduced two mini-multiplex assays that amplify 10 overlapping control region (CR) fragments in two separate multiplex PCRs, which brought successful CR consensus sequences from even highly degraded DNA extracts. This procedure requires a total of 20 sequencing reactions per sample, which is laborious and cost intensive. For only moderately degraded samples that we encounter more frequently with typical mtDNA casework material, we developed two new multiplex assays that use a subset of the mini-amplicon primers but embrace larger fragments (midis) and require only 10 sequencing reactions to build a double-stranded CR consensus sequence. We used a preceding mtDNA quantitation step by real-time PCR with two different target fragments (143 and 283 bp) that roughly correspond to the average fragment sizes of the different multiplex approaches to estimate size-dependent mtDNA quantities and to aid the choice of the appropriate PCR multiplexes with respect to quality of the results and required costs.
Institute of Legal Medicine, Innsbruck Medical University, Müllerstrasse 44, 6020 Innsbruck, Austria.
Cordula
C
Berger
Walther
W
Parson
D001483:Base Sequence; D053836:DNA Degradation, Necrotic; D016172:DNA Fingerprinting / Q000379:methods; D017931:DNA Primers / Q000737:chemistry / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005554:Forensic Medicine / Q000379:methods*; D015894:Genome, Human; D006197:Hair / Q000737:chemistry; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D004272:DNA, Mitochondrial