Chimerism Analysis

QTRACE® Chimerism Analysis

Background Information

The QTRACE® Genotyping Plates, Monitoring Assays and Software meet the needs of any research application that requires highly sensitive detection and quantification of the genome of one individual in the background of another individual or individuals. A genetic chimera is an organism with two or more genetically distinct cell populations, i.e. cell populations with different genomes. 

Chimerism can arise in humans through a variety of means, such as inheritance, maternal-fetal stem cell trafficking during gestation, blood vessel sharing in fraternal twin gestation, blood transfusions, bone marrow transplantation, cord blood transplantation, and solid organ transplantation. The presence of two distinct human genomes in a sample can also occur simply through the mining of human cells from more than one individual, for example, when two cell lines are cross-contaminated, or in forensic tissue samples.

Product Overview

The QTRACE® Analysis System uses qPCR technology and consists of DNA genotyping plates, 46 individual quantification assays, one reference assay, and QTRACE® Software. The QTRACE® INDEL Assays are able to differentiate, and then quantify, the contributors to a human-mixes DNA sample.

Each of the 46 assays is designed to a district bi-allelic insertion/deletion (INDEL) or copy number polymorphisms  in the human genome. The QTRACE® Software guides the user through reaction set-up for both genotyping and quantification and analyzes the collected data. The procedure for determining the level of a genome of interest in a sample consists of two parts: a genotyping test and a quantification test. 

Genotyping Test

In the initial genotyping test, the DNAs that comprise a mixed DNA sample are analyzed using a QTRACE® Genotyping Plate, to identify all of the informative assays for the samples. An informative assay is an assay for a marker allele that is present (positive) in one individual genome and absent (negative) in the other genome. The genotyping plate contains a duplicate set of assays: the 46 quantification assays and the reference (RNaseP) assay that serves as both a positive control and a No Template Control (NTC), pre-dispensed and dried in an optical qPCR plate. The QTRACE® qPCR Master Mix comes supplied with dUTP and UNG for built-in carryover contamination control.

The QTRACE® Genotyping Plates are packaged in air-tight, notched pouches for easy ambient storage and use. The typing protocol is a breeze. Once qPCR master mix and DNA are mixed, samples are dispensed to pre-arrayed assays in the optical plate.

Art. No. Name
RUO Not for use in diagnostic procedures - USA and Canada
121045 QTRACE® Genotyping Plates
121056 QTRACE® Genotyping Plate Pack - FAST
121066 QTRACE® Genotyping Plates - LC480
121129 MultiTRACE TM Genotyping Plate Rack - ABI 0.2 ml

Monitoring Test

In the monitoring (quantification) test, one or more of the informative assays identified in the genotyping test is used to quantify the DNA of interest in an unknown sample relative to a reference sample (calibrator). Any of the informative assays identified in the genotyping test can be used to perform a quantification test. The amount of the sample is determined relative to the amount of the same genome in the reference sample, and the result is expressed as a percentage (ratio). For example, a result of 5% indicates that there is  5% of genome A in the unknown sample relative to the reference sample. The simplest case assumes that the reference sample has 100% of genome A.

The informativeness of a multi-locus genotyping panel is a measure of the probability of finding at least one informative assay between two individual genomes (or DNA samples). Informativeness is calculated from the population frequency estimates of the alleles used to make up a multi-locus genotyping panel, and thus differs between ethnic populations. In addition, the informativeness of any panel of polymorphic loci is higher in unrelated individuals than in related individuals.

Once recipient specific markers have been found, quantification is performed to monitor engraftment. The fraction of DNA positive for the informative marker in the unknown composition is determined relative to the pure reference sample DNA and the result is expressed as a percentage (ratio).
The QTRACE® Assays represent a rapid (results are obtained within 2.5 hours) and sensitive (the validated detection limit is 0.1% minor component of a genomic DNA mixture using 150 ng DNA input) solution for chimerism testing.

The QTRACE® Software was designed specifically for the QTRACE® INDEL Assay Set. The software provides a streamlined workflow for both the genotyping and quantification tests. The sofware guides the user through assay setup, performs data analysis, generates results reports and stores the data collected for samples over time. 

Art. No. Name
RUO Not for use in diagnostic procedures - USA and Canada
211001 QTRACE® INDEL Assay 137
211002 QTRACE® INDEL Assay 148
211003 QTRACE® INDEL Assay 209
211004 QTRACE® INDEL Assay 235
211005 QTRACE® INDEL Assay 240
211006 QTRACE® INDEL Assay 267
211007 QTRACE® INDEL Assay 291
211008 QTRACE® INDEL Assay 305
211009 QTRACE® INDEL Assay 312
211010 QTRACE® INDEL Assay 326
211011 QTRACE® INDEL Assay 345
211012 QTRACE® INDEL Assay 356
211013 QTRACE® INDEL Assay 359
211014 QTRACE® INDEL Assay 361
211055 QTRACE® INDEL Assay 373
211064 QTRACE® INDEL Assay 386
211015 QTRACE® INDEL Assay 408
211016 QTRACE® INDEL Assay 425
211017 QTRACE® INDEL Assay 434
211018 QTRACE® INDEL Assay 469
211019 QTRACE® INDEL Assay 504
211054 QTRACE® INDEL Assay 519
211020 QTRACE® INDEL Assay 520
211021 QTRACE® INDEL Assay 531
211022 QTRACE® INDEL Assay 548
211023 QTRACE® INDEL Assay 601
211024 QTRACE® INDEL Assay 615
211025 QTRACE® INDEL Assay 626
211026 QTRACE® INDEL Assay 634
211027 QTRACE® INDEL Assay 650
211028 QTRACE® INDEL Assay 706
211065 QTRACE® INDEL Assay 710
211051 QTRACE® INDEL Assay 721
211029 QTRACE® INDEL Assay 736
211030 QTRACE® INDEL Assay 748
211053 QTRACE® INDEL Assay 755
211031 QTRACE® INDEL Assay 768
211032 QTRACE® INDEL Assay 784
211033 QTRACE® INDEL Assay 803
211052 QTRACE® INDEL Assay 819
211034 QTRACE® INDEL Assay 824
211035 QTRACE® INDEL Assay 832
211036 QTRACE® INDEL Assay 840
211037 QTRACE® INDEL Assay 854
211039 QTRACE® INDEL Assay 907
211040 QTRACE® INDEL Assay 916
211041 QTRACE® INDEL Assay 948
211042 QTRACE® INDEL Assay 954
311043 QTRACE® RNaseP Assay
311044 QTRACE® qPCR Master Mix
Art. No. Name
RUO Not for use in diagnostic procedures - USA and Canada
341048 QTRACE® Analysis Software

QTRACE® Assay Targets

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