# CRISPR-Edited Horses Spark Debate in the Polo World
These horses might look like ordinary horses, but there is something highly unusual about their genomes. They are the first of their species to have their DNA edited using CRISPR-Cas9,a technique that cuts the genome at a specific location to change gene expression and achieve a desired trait.
The horses are clones of the prize-winning steed Polo Pureza, but they have a tweak to myostatin – a gene involved in regulating muscle development – that is designed to quicken their pace. CRISPR was used in fetal fibroblasts (connective tissue cells) to generate embryos through cloning, and then the embryos were implanted into mares.
The development of these five CRISPR-edited horses ten months ago, by the non-profit research organization Kheiron Biotech in Buenos Aires, Argentina, is proving controversial among horse breeders in Argentina, where polo is extremely popular, Reuters reported on 30 August.
Critics are concerned that the technology threatens people’s livelihoods and that it will compromise the tradition of using selective breeding to generate elite horses. The Argentine Polo Association has now banned the use of gene-edited horses in the sport, following the led of similar organizations such as the International Federation for Equestrian Sports1, which banned the practice in 2019.
Some scientists, however, welcome the CRISPR horses. “It’s cool to show that CRISPR works and you can create CRISPR-altered horses,” says Molly McCue, a veterinary clinician scientist at the University of Minnesota in Minneapolis. “Horse[riders] frequently enough feel very strongly about breeding as an art and not a science, but really it is indeed both together,” she adds.
The CRISPR horses join a menagerie of gene-edited animals that have wide-ranging applications – mostly with the goal of improving agriculture. such efforts have now transformed from a research promise to a commercial reality, says Tad sonstegard, chief scientific officer at Acceligen, a company in Eagan, Minnesota that specializes in the precision breeding of livestock. Biological engineering ethicist Jeantine Lunshof, a