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Quantification of low-level genetically modified (GM) seed presence in large seed lots: a case study of GM seed in Canadian flax breeder seed lots

Published online by Cambridge University Press:  05 August 2011

Eric G. Lamb*
Affiliation:
Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SKS7N 5A8, Canada
Helen M. Booker
Affiliation:
Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SKS7N 5A8, Canada
*
*Correspondence Fax: +1306-966-1799 Email: eric.lamb@usask.ca

Abstract

The detection and quantification of the prevalence of genetically modified organism (GM) contamination in seed exports is a critical element of regulatory compliance. While the procedures to reliably detect high levels of GM contamination are well understood, no comparable statistical approaches are available for the quantification of levels of GM prevalence below the established detection rate of standard tests. We present a simple statistical approach based on simulation modelling for the quantification of low levels of GM contamination. The approach can be modified to match any sampling regime and can account for rates of false positive and negative assay results. The application of this method is demonstrated using the low level of contamination in Canadian flax breeder seed lots by the GM flax variety ‘Triffid’. We show that GM contamination is likely present in seed lots at rates between two GM seeds per million and six seeds per hundred thousand. We also show that this low level of presumed contamination is indistinguishable from the number of positive tests expected from a clean seed lot given the potential rates of false positive tests.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2011

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Supplementary material: File

Lamb Supplementary Material

Simulation model code and summary

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