Short Tandem Repeat (STR) genotyping is instrumental in data analysis for a wide range of human identification applications. Forensic samples from mass disasters and crime scene investigations are mixtures rather than single source; requiring additional analysis after obtaining DNA profiles (SWGDAM 2010 Guidelines). GeneMarker® HID software has all of the features of an expert system for consistent and accurate genotype determination, is compatible with all forensic chemistries, all CE genetic-analyzers (including ABI®PRISM-310-3100-3130-3730-3500) contains an embedded mixture analysis application; Identifying the number of contributors, automating repetitive calculations (Mixture-Ratios, Likelihood-ratios, Probability-of-Inclusion, Probability-of-Exclusion, Random-Man-Not-Excluded), ranks the most likely genotype combinations (with or without single source reference samples), deduces contributor genotypes, searches database. The mixture analysis application uses allele frequency tables (Identifiler®, PowerPlex®16, PowerPlex®ESX/ESI) or easily imports other populations, was developed using recommendations of the DNA Commission of the International Society of Forensic Genetics (Gill et al., 2006) and methods of Clayton et al., 1998 and Gill et al., 1998
Potential Mixture Samples Identified Automatically in Main Analysis Screen
Complete Mixture Analysis Application with or without Reference Samples
- Analysis Parameters easily set in dialog box
- Groups files by number of contributors
- Identifies contributor single source files
- Displays all possible allele combinations for contributors, color coding those that meet all mixture analysis parameters
- Determines major and minor contributors
- Searches database for exact match or potential near relatives
- Major Mx ratio, Residual, Heterozygous Imbalance for each combination of alleles in two contributor mixtures
- Likelihood Ratios at each marker and combined LR in two contributor mixtures
- Probability of Inclusion and Probability of Exclusion for any mixture sample (two contributors or three or more)
The Mixture Analysis Application is directly linked to the main analysis screen - avoiding the error prone, human transfer of data from one software package to another. Repetitive calculations are automated, according to user-set analysis parameters. In this example a single source suspect sample was not available and the mixture application deduced major contributor potential suspect profile. All results are presented in report tables that may be saved or copy/pasted into existing documents.
Search database using major contributor potential suspect from deconvolution of mixture sample
Click on the Search Database icon to locate matches to potential suspect profiles and calculate thenmixture statistics.
Mixture Analysis with Two Single Source Reference Files
The Report table has an option to display the trace files of the mixture and all single source profiles that are contained with the mixture allele calls.
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