Scientific theoretical foundation
CRISPR-Cas9 was not originally an artificial tool invented by humans, but rather originated from the bacterial immune system. Bacteria use CRISPR fragments to record the genetic information of viral invasions. When the same virus reappears, the Cas protein can recognize and cut the viral DNA, thus protecting the bacteria. Later, scientists transformed this natural mechanism into a programmable gene-editing tool. In 2020, Emmanuelle Charpentier and Jennifer A. Doudna were awarded the Nobel Prize in Chemistry for developing the CRISPR-Cas9 gene-editing method.
CRISPR-Cas9 can be understood as a "targeting system + molecular scissors." Guide RNA is responsible for finding specific target locations in the DNA; the Cas9 protein then cuts the DNA at those locations. After the DNA is cut, the cell initiates its own repair mechanism. Scientists can use this repair process to disable a gene, produce slight changes, or introduce new genetic information under specific conditions. Therefore, this technology is actually not very risky, and is even safer than conventional selective breeding and hybridization techniques. Today, CRISPR-Cas9 is one of the most mature and widely used fundamental technologies in life sciences. It is used in plant, insect, livestock, and human medicine.
Why CRISPR-Cas9 ?
FoxCode chose CRISPR-Cas9 because the project does not aim to alter foxes through long-term, heavily artificial domestication and captivity. Instead, it focuses on DNA modification in the early stages, granting foxes maximum freedom of life.
In FoxCode, CRISPR-Cas9 is primarily used to explore two directions: First, improving the visible health and appearance of foxes, such as more complete fur, more saturated coat colors, softer facial features, and smaller size, thereby leveraging public aesthetic preferences to reduce negative visual associations with foxes. Second, enhancing foxes' resistance to common diseases, especially mange. Mange causes severe hair loss, skin damage, pain, and even death in foxes, and reinforces public misconceptions about foxes being "unclean" and "disease-carrying." Enhancing disease resistance directly improves fox welfare and also helps improve public perception.