RESUMO
The analysis of mitochondrial DNA (mtDNA) from shed hairs has gained high importance in forensic casework since telogen hairs are one of the most common types of evidence left at the crime scene. In this systematic study of hair shafts from 20 individuals, the correlation of mtDNA recovery with hair morphology (length, diameter, volume, colour), with sex, and with body localisation (head, armpit, pubis) was investigated. The highest average success rate of hypervariable region 1 (HV 1) sequencing was found in head hair shafts (75%) followed by pubic (66%) and axillary hair shafts (52%). No statistically significant correlation between morphological parameters or sex and the success rate of sequencing was found. MtDNA sequences of buccal cells, head, pubic and axillary hair shafts did not show intraindividual differences. Heteroplasmic base positions were observed neither in the hair shafts nor in control samples of buccal cells.
Assuntos
DNA Mitocondrial/genética , Cabelo/química , Análise de Sequência de DNA , Adulto , Pareamento de Bases/genética , Feminino , Humanos , Masculino , Mucosa Bucal/citologia , Reação em Cadeia da PolimeraseRESUMO
Mitochondrial DNA control region sequences were determined in 109 unrelated German Caucasoid individuals from north west Germany for both hypervariable regions 1 (HV1) and 2 (HV2) and 100 polymorphic nucleotide positions (nps) were found, 63 in HV1 and 37 in HV2. A total of 100 different mtDNA lineages was revealed, of which 7 were shared by 2 individuals and 1 by 3 individuals. The probability of drawing a HV1 sequence match within the north west Germans or within published sets of south Germans and west Austrians is similar (within a factor of 2) to drawing a sequence match between any two of these three population samples. Furthermore, HV1 sequences of 700 male inhabitants of one village in Lower Saxony were generated and these showed a nearly linear increase of the number of different haplotypes with increasing number of individuals, demonstrating that the commonly used haplotype diversity measure (Nei 1987) for population samples tends to underestimate mtDNA diversity in the actual population.
Assuntos
DNA Mitocondrial/genética , Bases de Dados Factuais , Biblioteca Gênica , Variação Genética/genética , Genética Populacional , Análise de Sequência de DNA , Áustria , Feminino , Alemanha , Humanos , Masculino , Reação em Cadeia da Polimerase , ProbabilidadeRESUMO
The sequences of the hypervariable region 1 (HV1) of the mitochondrial DNA control region from multiple hair shafts from 10 unrelated individuals were compared to determine the frequency of differences in hairs from one individual. The extraction method described herein showed an average success rate of 67% for all 150 hair shafts tested in HV1. The mtDNA sequences from the hair shafts matched the sequences from the corresponding blood and saliva samples taken from the same donor and no evidence of heteroplasmy was found. The results emphasize the reliability of DNA extraction and mtDNA typing from human hair shafts for forensic purposes.
Assuntos
DNA Mitocondrial/genética , Cabelo/química , Feminino , Medicina Legal , Humanos , Masculino , Mutação Puntual , Análise de Sequência de DNARESUMO
A study was performed to determine the influence of garden soil on the deoxyribonucleic acid (DNA) recovery from teeth depending on the duration of storage. In the first series 24 teeth supplied by dentists were exposed to garden soil storage for a maximum of 18 weeks. Selected samples were excavated for DNA extraction at time intervals of 6, 12 and 18 weeks. For the second series 20 teeth were stored for one year in garden soil. Following phenol/chloroform extraction with decalcification (first series) and without decalcification prior to extraction (second series) DNA was quantified, amplified using the polymerase chain reaction (PCR) for the tandem repeat loci D1S80, tyrosine hydroxylase, intron 1 (TH01) and Von Willebrand factor, intron A (VWA) (first series), human alpha fibrinogen (FGA) (second series) and sequenced in the hypervariable regions 1 and 2 (HV1, HV2) of the mitochondrial DNA (second series). The DNA concentration of the extracts after the first 6 weeks in soil was reduced by more than 90%. Amplification and direct sequencing of HV1 and HV2 of the mitochondrial genome was the most successful DNA technique.
Assuntos
DNA/análise , DNA/química , Antropologia Forense/métodos , Odontologia Legal/métodos , Solo , Dente/química , Manchas de Sangue , Amplificação de Genes , Humanos , Incisivo , Dente Molar , Sequências de Repetição em TandemRESUMO
In 10,844 parent/child allelic transfers at nine short-tandem-repeat (STR) loci, 23 isolated STR mismatches were observed. The parenthood in each of these cases was highly validated (probability >99.97%). The event was always repeat related, owing to either a single-step mutation (n=22) or a double-step mutation (n=1). The mutation rate was between 0 and 7 x 10(-3) per locus per gamete per generation. No mutations were observed in three of the nine loci. Mutation events in the male germ line were five to six times more frequent than in the female germ line. A positive exponential correlation between the geometric mean of the number of uninterrupted repeats and the mutation rate was observed. Our data demonstrate that mutation rates of different loci can differ by several orders of magnitude and that different alleles at one locus exhibit different mutation rates.
Assuntos
Repetições de Microssatélites , Mutação , Adulto , Envelhecimento/genética , Alelos , Criança , Feminino , Frequência do Gene , Humanos , Masculino , Meiose , Dados de Sequência Molecular , Caracteres SexuaisRESUMO
Population genetic studies were carried out on a South Hungarian population (n = 111 individuals). The short tandem repeat (STR) systems Hum VWA, HumTH01, HumF13B, HumCD4, HumFES and HumFIBRA (FGA) were investigated by PCR amplification. All loci met Hardy-Weinberg expectations.
Assuntos
DNA/análise , Etnicidade/genética , Genética Populacional , Sequências Repetitivas de Ácido Nucleico , Alelos , Antígenos CD4/genética , Fator VIII/genética , Fibrinogênio/genética , Frequência do Gene , Humanos , Hungria , Proteínas Proto-Oncogênicas/genética , Tirosina 3-Mono-Oxigenase/genética , Fator de von Willebrand/genéticaRESUMO
Allele frequency data of the FGA locus were determined in eight population samples. No significant deviations from the Hardy Weinberg equilibrium were observed. The heterozygosity and mean exclusion chance ranged from 82 to 93% and 70 to 75% respectively.
Assuntos
Etnicidade/genética , Fibrinogênio/genética , Frequência do Gene , DNA/análise , Humanos , Sequências Repetitivas de Ácido NucleicoRESUMO
The sequences of the two hypervariable regions of the mitochondrial DNA control region (HV1 and HV2) from close maternal relatives (mother-child pairs) were compared to determine the frequency of mutations between two generations. A total of 68 blood samples were sequenced only in HVI and 86 were analysed for HV1 and HV2. The intergenerational comparison led to the identification of six heteroplasmic point mutations affecting the children only. In one case a heteroplasmy of the maternal sequence was resolved to homoplasmy in the corresponding sequence of the child.
