title: GMO quantification: valuable experience and insights for the future.
abstract: Cultivation and marketing of genetically modified organisms (GMOs) have been unevenly adopted worldwide. To facilitate international trade and to provide information to consumers, labelling requirements have been set up in many countries. Quantitative real-time polymerase chain reaction (qPCR) is currently the method of choice for detection, identification and quantification of GMOs. This has been critically assessed and the requirements for the method performance have been set. Nevertheless, there are challenges that should still be highlighted, such as measuring the quantity and quality of DNA, and determining the qPCR efficiency, possible sequence mismatches, characteristics of taxon-specific genes and appropriate units of measurement, as these remain potential sources of measurement uncertainty. To overcome these problems and to cope with the continuous increase in the number and variety of GMOs, new approaches are needed. Statistical strategies of quantification have already been proposed and expanded with the development of digital PCR. The first attempts have been made to use new generation sequencing also for quantitative purposes, although accurate quantification of the contents of GMOs using this technology is still a challenge for the future, and especially for mixed samples. New approaches are needed also for the quantification of stacks, and for potential quantification of organisms produced by new plant breeding techniques.
authors.affiliation: Department of Biotechnology and Systems Biology, National Institute of Biology (NIB), Večna pot 111, 1000, Ljubljana, Slovenia, mojca.milavec@nib.si.
authors.forename: Mojca
authors.initials: M
authors.lastname: Milavec
authors.forename: David
authors.initials: D
authors.lastname: Dobnik
authors.forename: Litao
authors.initials: L
authors.lastname: Yang
authors.forename: Dabing
authors.initials: D
authors.lastname: Zhang
authors.forename: Kristina
authors.initials: K
authors.lastname: Gruden
authors.forename: Jana
authors.initials: J
authors.lastname: Zel
mesh_terms: D000818:Animals; D004247:DNA / Q000032:analysis / Q000235:genetics*; D019075:Electrophoresis, Capillary / Q000379:methods; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D030781:Organisms, Genetically Modified / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*
chemical_list: D004247:DNA