Target analyte stability


Plant and food components break down over the course of time and because of processing. It is important to closely study the molecules used to identify GMOs to make sure that even after some degradation, they still yield accurate results. Therefore, this task aims to make an assessment of the stability of a wide range of potential target molecules for GMO testing.


Researchers are comparing the stability and structure of various possible analytes or analyte components. They also look for differences between DNA versus protein degradation.

  • With DNA, the team looks into the stability of genes with different compositions of GC versus AT base pairs, the latter of which have weaker pairing. Another topic being investigated is if coding vs. non-coding DNA sequences have differing levels of stability, or if genetic regions with transposable elements are intrinsically less stable.
  • With proteins, different domains within a protein molecule have different labels of stability, and they are studied to see if this could influence the results of protein-based GMO testing.

The types of samples being tested for instability include, but are not limited to:

  • Cloned plasmid DNA markers containing sequences characteristic of particular crop species or GMOs
  • Seed and grain of varieties of a single transgenic event
  • Leaves and kernels of different cultivars of a single crop species
  • Near 100 percent pure GM material of a single event for processing

The way, samples are prepared for the lab could also be a source of biased instability effects on targeted analytes. Therefore, researchers look for biases depending on the type of tissue taken for analysis, the processing state of the sample (e.g. heated versus air dried or dry milled versus wet milled), the DNA extraction method, and the quantitative detection method used.


The number of scientific publications reporting on possible bias in GM quantity estimations using real-time PCR based methods is growing, and cannot be ignored. However, in most cases the experimental design does not permit clear conclusions to be drawn, because data produced could have several possible explanations. 

GMO testing: Status report on the target analyte instability bias studies
This report describes the results of studies on target analyte instability. The purpose of the report is to assist the stakeholders in interpreting analytical results and implementing analytical procedures that may minimise the risk of bias of the resulting GMO quantity estimates.


National Veterinary Institute (NVI), Norway
Department of Plant Genetics and Breeding (Institute for Agricultural and Fisheries Research – ILVO), Ghent, Belgium
GeneScan Analytics GmbH, Germany
Consejo Superior de Investigaciones Cientificas (CSIC-IRTA), Spain