Your orange kitty may have a secret genetic pathway for color pigmentation that scientists have never seen before, according to some new studies. Cats, as we all know, are pretty much flawless creatures. They have evolved with minimal changes and maximum efficiency, making them the genetic gold standard. Leslie Lyons, a cat genetics expert at the University of Missouri, believes that cats hold the key to understanding genetics. She says that studying their coat colors has taught us a lot about modern genetics. However, the color orange has always been a mystery in cats. Most of the time, orange fur is found in male cats due to a mutation on the X chromosome. Scientists have been scratching their heads for years trying to figure out which gene is responsible for these pumpkin-colored felines.
Two new papers published in Current Biology on Thursday shed some light on this long-standing mystery. Researchers from Stanford University and Kyushu University in Japan discovered a unique genetic pathway that sets orange cats apart from the rest. They found that a small deletion in the X chromosome increases the activity of a gene called Arhgap36, which was never before linked to pigmentation. This gene seems to be responsible for turning the cat’s melanin-producing cells orange. These groundbreaking findings put an end to years of speculation about why some house cats sport a ginger coat. Christopher Kaelin, a geneticist who led the Stanford study, explains that orange fur in cats is not caused by a specific “orange gene” but rather by a mutation in an unknown gene. This mutation leads to changes in the cat’s DNA, resulting in the unique orange coloration.
The abundance of male orange cats has long hinted at a sex-linked trait tied to the X chromosome. Female mammals, including cats, have a mechanism called X-inactivation that randomly turns off one of their two X chromosomes to prevent genetic complications. Male cats, on the other hand, have one X and one Y chromosome. If a male cat inherits the orange mutation, it will have entirely orange fur. Female cats with the mutation may display patches of orange, brown, or black fur depending on which X chromosome is activated in different parts of their skin. Scientists had been narrowing down the location of this key mutation in the cat genome over the years. Hiroyuki Sasaki, a geneticist from Kyushu University, and his team sequenced the whole genomes of cats with various coat colors to pinpoint variations on the X chromosome. The Stanford team, on the other hand, analyzed DNA sequences from orange and non-orange cats to identify the mutation near the Arhgap36 gene. This unusual mutation doesn’t disrupt the gene’s expression but affects its activity in melanin-producing cells. Leslie Lyons, who contributed to cat genomic resources in the Stanford study, believes that these findings highlight the complex interplay of genes and developmental processes in shaping a cat’s health. Orange and tortoiseshell cats are known for their playful and friendly nature, but there’s no scientific evidence linking coat colors to behavior. Researchers are curious to explore whether the Arhgap36 mutation could influence brain activity and behavior in cats, given that this gene is also expressed in the brain and hormonal glands. Greg Barsh, a geneticist involved in the Stanford study, suggests that the orange mutation may have simply arisen by chance because people find orange cats attractive and end up saving them.
