Technique Will Speed Genetic Engineering

A quick and easy way to remove so-called “marker genes” that are used during the genetic engineering of plants has been developed by researchers at the U.S. Department of Agriculture’s research center at Albany. The development is likely to lead to quicker approval of genetically engineered foodstuffs.

The markers are inserted into a plant’s genes along with a desired gene so that researchers will have an easy way to tell if the insertion was successful. A typical marker might provide resistance to an antibiotic that would otherwise kill the plant cells. But once researchers know the insertion is successful, the marker is no longer needed and its presence may complicate the approval process.

Geneticist David W. Ow and his colleagues at the Department of Agriculture reported Sunday in the Proceedings of the National Academy of Sciences that they genetically engineered two types of plants. One contained the gene for a naturally occurring “editing” enzyme that will cut certain types of genetic material. The second contained the desired gene along with the marker gene, which was flanked by bits of genetic material that the enzyme could easily cut.

When these parents are bred, the editing gene cuts away the marker gene. Further crossing of these offspring then eliminates the editing gene through natural laws of inheritance, leaving behind only the beneficial gene.