Genetically engineered animals provide important insights into the molecular basis of health and disease. Research has focused mainly on genetically modified mice, although other species, such as pigs, are more similar to human physiology. Researchers have now generated chickens and pigs in which target genes in desired organs can be efficiently altered.

CRISPR/Cas9 enables desired gene manipulations

CRISPR/Cas9 is a tool to rewrite DNA information. Genes can be inactivated or specifically modified using this method. The CRISPR/Cas9 system consists of two components.

The gRNA (guide RNA) is a short sequence that binds specifically to the DNA segment of the gene that is to be modified. The Cas9 nuclease, the actual «gene scissors,» binds to the gRNA and cuts the respective section of the target DNA. This cut activates repair mechanisms that can inactivate gene functions or incorporate specific mutations.

Healthy chickens and pigs with integrated gene scissors

«The generated animals provide the gene scissors, the Cas9 protein, right along with them. So all we have to do is to introduce the guide RNAs to get animals which have specific genetic characteristics,» explains Benjamin Schusser, Professor of Reproductive Biotechnology at the TUM. «The initial generation of these animals took about three years. Cas9 can now be used at all stages of animal development, since every cell in the body permanently possesses the Cas9 protein. We have been successfully able to utilize this technique in chicken embryos as well as in living pigs.»

The healthy chickens and pigs produced by the researchers thus possess the Cas9 nuclease in all organs studied. This is particularly useful in biomedical and agricultural research.

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Materials provided by Technical University of Munich (TUM). Note: Content may be edited for style and length.