Characterising stutter in forensic STR multiplexes

Brookes, Clare; Bright, Jo‐Anne; Harbison, SallyAnn; Buckleton, John

doi:10.1016/j.fsigen.2011.02.001

Cited by 126 publications

(75 citation statements)

References 16 publications

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“…marker and the number of repeat motifs of an allele [15]. The default locus-specific stutter filter values included in the stutter filters are based on all stutters observed in this study.…”

Section: Stuttermentioning

confidence: 99%

Developmental validation of QIAGEN Investigator® 24plex QS Kit and Investigator® 24plex GO! Kit: Two 6-dye multiplex assays for the extended CODIS core loci

Kraemer

Prochnow

Bussmann

et al. 2017

Forensic Science International: Genetics

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The original CODIS database based on 13 core STR loci has been overwhelmingly successful for matching suspects with evidence. In order to increase the power of discrimination, reduce the possibility of adventitious matches, and expand global data sharing, the CODIS Core Loci Working Group determined the expansion of the CODIS core loci to 20 STR plus three additional "highly recommended" loci (SE33, DY391, Amelogenin) Hares, 2015Hares, , 2012. The QIAGEN Investigator 24plex QS and Investigator 24plex GO! Kits are 6-dye multiplex assays that contain all markers of the expanded 23 CODIS core loci along with a unique internal performance control that is co-amplified with the STR markers. The "Quality Sensor" generates additional information for quality control and performance checks. Investigator 24plex QS is designed for purified DNA from casework and reference samples, whereas 24plex GO! is dedicated to direct amplification of reference samples, like blood or buccal cells on FTA or swabs.A developmental validation study was performed on both assays. Here, we report the results of this study which followed the recommendations of the European Network of Forensic Science Institutes (ENFSI) [3] and the Revised Validation Guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM) [4]. Data included are for PCR-based procedures e.g. reaction conditions, effects of PCR annealing temperature variations, amplification cycles or cyclers, sensitivity (also in the context of the Quality Sensor), performance with simulated inhibition, stability and efficiency, precision, reproducibility, mixture study, concordance, stutter, species specificity, and case-type samples. The validation results demonstrate that the Investigator 24plex QS and Investigator 24plex GO! Kits are robust and reliable identification assays as required for forensic DNA typing in forensic casework analysis and databasing.

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Section: Stuttermentioning

confidence: 99%

Developmental validation of QIAGEN Investigator® 24plex QS Kit and Investigator® 24plex GO! Kit: Two 6-dye multiplex assays for the extended CODIS core loci

Kraemer

Prochnow

Bussmann

et al. 2017

Forensic Science International: Genetics

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“…Based on the circumstances it is also possible to observe stutter that is two repeats shorter or one repeat longer (Krenke et al 2005). Stutter is more prevalent for STR loci with AT-rich DNA sequences and very regular repeat units and should be measured during the validation phase (Walsh et al 1996;Mulero et al 2008;Brookes et al 2012). Even though it is possible to calculate the expected percentage of stutter for each STR locus and incorporate this value into the data interpretation, stutter can make mixture interpretation difficult and can be mistaken for a minor component allele.…”

Section: Str Data Analysismentioning

confidence: 99%

Forensic DNA Analysis

Prinz¹,

Lessig²

2014

Handbook of Forensic Medicine

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“…In order to characterize the amount of stutter two quantities, the stutter ratio and the stutter proportion have been defined in the literature [10]. The stutter ratio is given by r s = h s /h a , and the stutter proportion by p s = h s /(h s + h a ), where h s is the peak height of the stutter peak and h a the peak height of the allelic peak.…”

Section: Stuttermentioning

confidence: 99%

“…In our model (1), the linear relationship in (2) and (3) is expressed by a multiplication with the stutter matrix S. Although this model is simple, it is widely used to describe the effects of stutter [10], [13], [16]. It has been observed that the stutter proportion is not constant within a locus.…”

Section: Stuttermentioning

confidence: 99%

“…In general, it increases with increasing repeat number. In [10], [11] it was reported that the longest uninterrupted sequence (LUS) in an allele might be more appropriate than the repeat number of an allele to describe the increase of the stutter proportion. Our approach to model stutter is linear in the sense that the stutter peak height is always a fixed proportion of the hypothetical allelic peak height before stutter, according to (2).…”

Section: Stuttermentioning

confidence: 99%

See 1 more Smart Citation

A signal model for forensic DNA mixtures

Monich

Grgicak

Cadambe

et al. 2014

2014 48th Asilomar Conference on Signals, Systems and Computers

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Abstract-For forensic purposes, short tandem repeat allele signals are used as DNA fingerprints. The interpretation of signals measured from samples has traditionally been conducted by applying thresholding. More quantitative approaches have recently been developed, but not for the purposes of identifying an appropriate signal model. By analyzing data from 643 single person samples, we develop such a signal model. Three standard classes of two-parameter distributions, one symmetric (normal) and two right-skewed (gamma and log-normal), were investigated for their ability to adequately describe the data. Our analysis suggests that additive noise is well modeled via the log-normal distribution class and that variability in peak heights is well described by the gamma distribution class. This is a crucial step towards the development of principled techniques for mixed sample signal deconvolution.

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Characterising stutter in forensic STR multiplexes

Cited by 126 publications

References 16 publications

Developmental validation of QIAGEN Investigator® 24plex QS Kit and Investigator® 24plex GO! Kit: Two 6-dye multiplex assays for the extended CODIS core loci

Developmental validation of QIAGEN Investigator® 24plex QS Kit and Investigator® 24plex GO! Kit: Two 6-dye multiplex assays for the extended CODIS core loci

Forensic DNA Analysis

A signal model for forensic DNA mixtures

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