FEATURE ARTICLE
GENE EDITING – IS IT A REALITY? by Darrell Wilkes, Ph.D., International Brangus Breeders Association (IBBA) executive vice president The term “gene editing” has been kicked around for several years and may have created more confusion than enlightenment. The thought of it might also create some anxiety among seedstock breeders who fear that their many years of selection and traditional genetic improvement could be leap-frogged by some mad scientist in a lab. I have had conversations with breeders who fear that such technology will result in a complete restructuring of the seedstock industry such that large biotech companies will “take over” the seedstock business. The fear is that the biotech giants will hold patents on certain genes or gene combinations and everybody else will be reduced to multiplying their genetics under a license agreement. Simply put, such fears are unfounded. If one considers the broad spectrum of what is generally called “genetic engineering” and create a scale of one to ten with one being the most simple and basic applications and ten being the most extreme (almost science-fiction like) applications, gene editing would be scored a 1. Gene editing, as used in reference to cattle, will not create any genetic characteristics that could not otherwise be created through normal breeding strategies. An example may help explain the simple nature of gene editing. As most cattle breeders now know, DNA is made up of nucleotides. There are only four them in DNA. They are Adenine, Thymine, Guanine and Cytosine – and are
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abbreviated with the first letter of each – A T G C. The sequence of these letters provides the instructions for making a specific protein. A gene is nothing more than a string of these letters. For the sake of simplicity, let’s assume the following sequence of nucleotides codes for black hair color: A A T T C C G G. Let’s assume that the gene for red hair color is A T A T C C G G. The only difference is that the second and third letters are switched. One application of gene editing is to simply cut the DNA strand with special chemical scissors and literally switch the order of the letters. This is truly an edit. It is not unlike editing a misspelled wrod (word). In this simple example, it does not involve inserting a gene from a different breed or even a different animal from the same breed. It simply rearranges the nucleotides that are already there and it creates a gene variant (allele) that already exists – in this illustration, a gene for red hair. Does this mean that you can create a Red Brangus from a Black Brangus, for example? Yes, that can be done. The rest of the story is what I have discovered is confusing to people. How does this “micro surgery” of DNA change the color of an animal? It does not change the color of the source animal. The process requires that a new animal be created with the edited DNA. There are a couple ways to do this, but a common one is through cloning, which is already a proven and commercially available technology. You take a regular
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