RESUMO
Identification of the potential donor(s) of human germline-derived cells is an issue in many criminal investigations and in paternity testing. The experimental and statistical methodology necessary to work up such cases is well established but may be more challenging if monozygotic (MZ) twins are involved. Then, elaborate genome-wide searches are required for the detection of early somatic mutations that distinguish the cell sample and its donor from the other twin, usually relying upon reference material other than semen (e.g. saliva). The first such cases, involving either criminal sexual offenses or paternity disputes, have been processed successfully by Eurofins Genomics and Forensics Campus. However, when presenting the experimental results in court, common forensic genetic practice requires that the residual uncertainty about donorship is quantified in the form of a likelihood ratio (LR). Hence, we developed a general mathematical framework for LR calculation, presented herein, which allows quantification of the evidence in favour of the true donor in the respective cases, based upon observed DNA sequencing read counts.
Assuntos
Genética Forense/métodos , Mutação em Linhagem Germinativa , Paternidade , Gêmeos Monozigóticos/genética , Desenvolvimento Embrionário/genética , Marcadores Genéticos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Conceitos Matemáticos , Modelos Genéticos , Análise de Sequência de DNA , Espermatozoides/químicaRESUMO
Monozygotic (MZ) twins are considered being genetically identical, therefore they cannot be differentiated using standard forensic DNA testing. Here we describe how identification of extremely rare mutations by ultra-deep next generation sequencing can solve such cases. We sequenced DNA from sperm samples of two twins and from a blood sample of the child of one twin. Bioinformatics analysis revealed five single nucleotide polymorphisms (SNPs) present in the twin father and the child, but not in the twin uncle. The SNPs were confirmed by classical Sanger sequencing. Our results give experimental evidence for the hypothesis that rare mutations will occur early after the human blastocyst has split into two, the origin of twins, and that such mutations will be carried on into somatic tissue and the germline. The method provides a solution to solve paternity and forensic cases involving monozygotic twins as alleged fathers or originators of DNA traces.
Assuntos
Paternidade , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA/métodos , Gêmeos Monozigóticos/genética , Análise Química do Sangue , DNA/isolamento & purificação , Feminino , Humanos , Masculino , Reação em Cadeia da Polimerase , Sêmen/química , SoftwareRESUMO
Serogroup A meningococci are a leading cause of bacterial meningitis in children and young adults worldwide. However, the genetic basis of serogroup A strains' virulence and their epidemiological properties remain poorly understood. Therefore, we sequenced the complete genome of the transformable Neisseria meningitidis serogroup A strain WUE2594.
Assuntos
DNA Bacteriano/química , DNA Bacteriano/genética , Genoma Bacteriano , Neisseria meningitidis Sorogrupo A/genética , Alemanha , Humanos , Meningite Meningocócica/microbiologia , Dados de Sequência Molecular , Neisseria meningitidis Sorogrupo A/isolamento & purificação , Análise de Sequência de DNARESUMO
The methylotrophic yeast Pichia pastoris is widely used for the production of proteins and as a model organism for studying peroxisomal biogenesis and methanol assimilation. P. pastoris strains capable of human-type N-glycosylation are now available, which increases the utility of this organism for biopharmaceutical production. Despite its biotechnological importance, relatively few genetic tools or engineered strains have been generated for P. pastoris. To facilitate progress in these areas, we present the 9.43 Mbp genomic sequence of the GS115 strain of P. pastoris. We also provide manually curated annotation for its 5,313 protein-coding genes.
