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1.
Forensic Sci Int ; 164(1): 33-44, 2006 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-16343834

RESUMO

Recently, there has been much debate about what kinds of genetic markers should be implemented as new core loci that constitute national DNA databases. The choices lie between conventional STRs, ranging in size from 100 to 450 bp; mini-STRs, with amplicon sizes less than 200 bp; and single nucleotide polymorphisms (SNPs). There is general agreement by the European DNA Profiling Group (EDNAP) and the European Network of Forensic Science Institutes (ENFSI) that the reason to implement new markers is to increase the chance of amplifying highly degraded DNA rather than to increase the discriminating power of the current techniques. A collaborative study between nine European and US laboratories was organised under the auspices of EDNAP. Each laboratory was supplied with a SNP multiplex kit (Foren-SNPs) provided by the Forensic Science Service, two mini-STR kits provided by the National Institute of Standards and Technology (NIST) and a set of degraded DNA stains (blood and saliva). Laboratories tested all three multiplex kits, along with their own existing DNA profiling technique, on the same sets of degraded samples. Results were collated and analysed and, in general, mini-STR systems were shown to be the most effective. Accordingly, the EDNAP and ENFSI working groups have recommended that existing STR loci are reengineered to provide smaller amplicons, and the adoption of three new European core loci has been agreed.


Assuntos
Degradação Necrótica do DNA , Impressões Digitais de DNA/métodos , Genética Forense/métodos , Polimorfismo de Nucleotídeo Único , Sequências de Repetição em Tandem , Análise de Variância , Sangue , Europa (Continente) , Genótipo , Humanos , Reação em Cadeia da Polimerase , Saliva
2.
Forensic Sci Int ; 154(1): 62-77, 2005 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-16182950

RESUMO

A single nucleotide polymorphism (SNP) multiplex has been developed to analyse highly degraded and low copy number (LCN) DNA template, i.e. <100 pg, for scenarios including mass disaster identification. The multiplex consists of 20 autosomal non-coding loci plus Amelogenin for sex determination, amplified in a single tube PCR reaction and visualised on the Applied Biosystems 3100 capillary electrophoresis (CE) system. Allele-specific primers tailed with shared universal tag sequences were designed to speed multiplex design and balance the amplification efficiencies of all loci through the use of a single reverse and two differentially labelled allele denoting forward universal primers. As the multiplex is intended for use with samples too degraded for conventional profiling, a computer program was specifically developed to aid interpretation. Critical factors taken into account by the software include empirically determined extremes of heterozygous imbalance (Hb) and the drop-out threshold (Ht) defined as the maximum peak height of a surviving heterozygous allele, where its partner may have dropped out. The discrimination power of the system is estimated at 1 in 4.5 million, using a White Caucasian population database. Comparisons using artificially degraded samples profiled with both the SNP multiplex and AMPFISTR SGM plus (Applied Biosystems) demonstrated a greater likelihood of obtaining a profile using SNPs for certain sample types. Saliva stains degraded for 147 days generated an 81% complete SNP profile whilst short tandem repeats (STRs) were only 18% complete; similarly blood degraded for 243 days produced full SNP profiles but only 9% with STRs. Reproducibility studies showed concordance between SNP profiles for different sample types, such as blood, saliva, semen and hairs, for the same individual, both within and between different DNA extracts.


Assuntos
Impressões Digitais de DNA/métodos , Polimorfismo de Nucleotídeo Único , Amelogenina , Animais , Análise Química do Sangue , Primers do DNA , Proteínas do Esmalte Dentário/genética , Eletroforese Capilar , Feminino , Frequência do Gene , Ligação Genética , Heterozigoto , Homozigoto , Humanos , Masculino , Reação em Cadeia da Polimerase , Grupos Raciais/genética , Saliva/química , Sêmen/química , Análise de Sequência de DNA , Análise para Determinação do Sexo , Especificidade da Espécie , Sequências de Repetição em Tandem
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