Unintended consequences

• Rabbits: Deleting MSTN (a muscle-growth-limiting gene) to make leaner animals led to enlarged tongues
• Pigs: Deleting MSTN led to having an extra thoracic vertebrae and a slight fading in color after cooking
• Sheep: Deleting MSTN led to enlarged embryos that required c-sections; Altering ASIP (a coat-color gene) to make darker coats led to three-quarter miscarriage rate
• Cattle: Deleting a single amino acid on the coat color gene to lighten their coats led to premature deaths; Enabling cold-weather cattle to thrive in warmer climates led to premature deaths

"Big Tongues and Extra Vertebrae: The Unintended Consequences of Animal Gene Editing" (2018 Dec 14)