Genetic basis of orange cat's ginger hue is traced to a specific gene deletion

In a groundbreaking study led by researchers at Harvard University, the gene responsible for most orange coat colors in domestic cats has been identified. This discovery, announced in June 2020, has shed light on the genetic mystery that has puzzled cat enthusiasts for centuries.

The team, led by Christopher Kaelin, examined the genes of around 30 cats to find DNA features shared only by those with orange fur. Their examination revealed a deleted stretch of approximately 5,000 DNA base pairs near the gene Arhgap36 in the cat genome. Interestingly, this removed bit was not within the gene itself but close enough to affect its activity.

The same deletion was found in all orange cats from a global database of 258 kitties, while non-orange ones lacked it. This finding suggests that the trait of orange fur in domestic cats may have been passed down from a single ancestral cat that lived more than 900 years ago, as indicated by historical paintings of calicos.

Before these studies, researchers were unaware of Arhgap36's involvement in a cat's coloring. The gene carries instructions for making a certain protein. In pigment-making cells, the nearby deletion boosts how much of that protein it makes. This increase in protein production stops genes needed to make the brown-black pigment from turning on, resulting in the production of a yellow-red pigment, thus explaining the orange fur.

A team in Japan has also identified the same deletion in their study of DNA from almost 60 cats, further supporting the findings of the Harvard team. The role of the Arhgap36 gene in ginger hues is unique to domesticated felines, making it a fascinating area for future research.

This discovery not only deepens our understanding of cat genetics but also opens up possibilities for genetic engineering to breed cats with specific coat colors. However, it is crucial to approach such advancements with care, ensuring ethical considerations are at the forefront of any future research.