Methods and systems for prediction of a dna profile mixture ratio

Abstract

A system configured to characterize a ratio of contributors to a DNA mixture within a sample, the system including: a sample preparation module configured to generate initial data about the DNA mixture within the sample; a processor comprising a ratio of contributors determination module configured to: (i) receive the generated initial data; (ii) analyze the generated initial data to determine the ratio of contributors to the DNA mixture within the sample; and an output device configured to receive the determined ratio of contributors from the processor, and further configured to output information about the received determined ratio of contributors.

What is claimed is: 
     
         1 . A system configured to determine a ratio of any contributors to a forensic DNA sample, the system comprising:
 a sample preparation module configured to generate DNA sequence data representing a plurality of markers from a forensic DNA sample;   a processor programmed to receive the DNA sequence data and to determine a ratio of contributors to the forensic DNA sample using the DNA sequence data, wherein the processors is programmed to determine the ratio of contributors by
 identifying each of the plurality of markers within the forensic DNA sample mixture that exhibit a maximum number of alleles, 
 determining all possible scenarios for contributors to the forensic DNA sample mixture based on the determined maximum number of alleles, 
 evaluating whether each possible scenario is a valid scenario based on whether the possible scenario has every allele appearing in one of the plurality of markers appears at least once, 
 determining an initial mixture ratio for each valid scenario, 
 identifying any clusters formed by a group of initial mixture ratios containing only one ratio for each of the plurality of markers, 
 selecting any compact clusters having a distance between a centroid of the cluster to the initial mixture that is below a certain threshold, wherein the centroid of selected compact clusters represents a candidate profile mixture ratio, 
 comparing all of the candidate profile mixture ratios to all the of the mixture ratios across all of the plurality of markers to identify the ratio of contributors to the forensic DNA sample based on which of the candidate profile mixture ratios has the highest number of markers containing at least one similar ratio at each of the plurality of markers, 
   an output device coupled to the processor and configured to receive the ratio of contributors to the forensic DNA sample and to output the ratio of contributors to the forensic DNA sample.   
     
     
         2 . The system of  claim 1 , wherein the identification of each of the plurality of markers within the forensic DNA sample mixture that exhibit the maximum number of alleles includes the maximum number of alleles minus one. 
     
     
         3 . The system of  claim 2 , wherein the processor is programmed to remove any statistical outliers from the clusters formed by a group of initial mixture ratios containing only one ratio for each of the plurality of markers. 
     
     
         4 . The system of  claim 3 , wherein the processor is programmed to remove the statistical outliers using Chebyshev's Inequality. 
     
     
         5 . The system of  claim 4 , wherein the at least one similar ratio is determined by a Euclidean distance that is below a predetermined threshold. 
     
     
         6 . The system of  claim 5 , wherein processor is configured all a user to set the predetermined threshold. 
     
     
         7 . The system of  claim 1 , wherein the sample preparation module is configured to generate the DNA sequence data using capillary electrophoresis based fragment analysis. 
     
     
         8 . The system of  claim 1 , wherein the sample preparation module is configured to generate the DNA sequence data using polymerase chain reaction sequencing. 
     
     
         9 . The system of  claim 1 , wherein the forensic DNA sample includes DNA from more than two individuals. 
     
     
         10 . The system of  claim 1 , wherein the forensic DNA sample includes DNA from more than one species.