Identification of transgenic organisms

Researchers at Goethe University Frankfurt have developed a concept called AGameOfClones, which allows them to distinguish whether transgenic organisms carry an inserted foreign gene on one or on both chromosomes. This facilitates breeding and also benefits animal welfare.

To understand biological processes, researchers often use model organisms such as mice, zebrafish and various species of insects, with the underlying idea that their discoveries can also be transferred to other species. A common technique is genetic manipulation, a process where a foreign gene (also known as a transgene) is inserted into one of the chromosomes of the target organism. Many model organisms have pairs of chromosomes—one inherited from each parent. In these pairs, the genes are arranged in the same order but are not necessarily identical.

Newly created transgenic organisms, however, carry the transgene on only one of the chromosomes. This can pose a problem for researchers because many experiments require individuals that carry the foreign gene on both. Unfortunately, only costly and error-prone methods can distinguish between these individuals. To overcome these drawbacks, Frederic Strobl from the research group led by Professor Ernst Stelzer at the Buchmann Institute for Molecular Life Sciences of Goethe University Frankfurt developed a genetic concept called AGameOfClones and applied it to the red flour beetle Tribolium castaneum.

In this approach, the foreign gene also contains sequences for two protein markers with different fluorescent colours. After several generations of breeding, two variants of the transgene emerge that each retain only one marker. This means that in the following generation, the descendants with both markers must be the progeny that carry the transgene on both chromosomes.

The AGameOfClones concept has several major advantages: Individuals with different markers can be easily identified and the procedure is cost-efficient, reliable and can be applied to almost all model organisms. This benefits especially animal welfare, since individuals that are unsuitable for use in experiments can be excluded as soon as the markers become detectable.