After more than 60 years of research, scientists have finally revealed because some cats have the orange hair. The answer is hidden in their genes, in particular in a small portion of the chromosome x. Two research teams – one from Stanford University in the United States and the other of Kyushu University in Japan – have independently discovered one genetic mutation It is precisely precise that everything changes: it is the Loss of a small DNA segmenta so -called “deletion”, which affects the activity of a gene called Arhgap36.
A fact that not only confirms the importance of the mutation, but He also explains why orange cats are almost always male: being the gene located on the former, to the males (who have only one chromosome x) a copy of the mutation is enough to become orange. The females, having two, must inherit it from both parents to have a uniform color. If the mutation is present in one chromosome, however, the result is a “CHRISH” cloakas in the Calico, where some areas express the gene and become orange, others do not.
Like the mutation on the X chromosome makes the cats become orange: the details of scientific research
But what exactly happens? This gene, when active, stimulates the production of a pigment called feomelaninresponsible for warm colors such as yellow, red and – in fact – theorange. In cats with mutation, arhgap36 It is expressed up to 13 times more than normaland this leads to a real orange explosion in the cloak. The interesting thing is that the mutation is not located directly in the gene itself, but just before it, in an area of DNA which normally regulates how much a gene should be turned on or off. When this “switch” is missing, the gene remains turned on more than necessary, making the hair orange.
To demonstrate all this were two independent studies, previewed on the Biorxiv platform (therefore Waiting for official review). The first was led by the geneticist Greg Barsh Stanford University. His team analyzed the cells of orange cats and noticed that the gene Arhgap36 it was much more active than normal, about 13 times more. At first, the researchers thought there was a mutation within the gene, but with great surprise they discovered that the change was in a region which does not contain instructions to build proteinsbut which acts as a “regulator” of gene expression. In practice, it is as if a switch that normally holds the gene under control had skipped.
To understand if this mutation were common, the researchers consulted an archive of 188 Feline genomes. Result? All cats with the orange, Calico or Turtle cloak They had exactly the same deletion on the X chromosome.
Also the second study, coordinated by the Japanese geneticist Hidehiro Toh of the University of Kyushu, has reached the same conclusions. His group has analyzed over 250 genomes of cats from all over the world, finding the same identical deletion. In addition, he observed that in the cats Calico theActivities of the ARHGAP36 gene is higher in the orange areas of the cloakwhile falling into black or brown areas. This confirmation that The color variation depends on how much the gene is “on” in that specific part of the body.
An ancient and mysterious mutation: how widespread it is and where it comes from
Research revealed that the responsible mutation of orange hair in cats is present in specimens from all over the world. This suggests that the deletion in the ARHGAP36 gene has appeared only once in the evolutionary history of the domestic cat and then spread through natural selection and human breeding. According to the geneticist Christopher Kaelin, the presence of orange cats in ancient Chinese paintings dating back to XII century It indicates that this mutation is ancient and widely widespread.
Currently, researchers are considering the DNA analysis of Mummified cats or Egyptian depictions To determine if the mutation was also present in antiquity. This small genetic anomaly could provide valuable information on the history of the cat’s abomestication. Speaking of abdominal, many cat owners claim that orange cats are more sociable, affectionate or “chaotic“Compared to others. However, scientists are cautious in drawing definitive conclusions. The arhgap36 gene is also active in the brain and hormonal glands, therefore it could theoretically influence behavior. However, studies have so far not detected significant differences in brain activity between orange and non -orange cats.
According to Kaelin, the lively reputation of orange cats is more likely to be linked to the fact that they are almost all males, and males tend to be more expansive or turbulent. However, further studies could clarify if there is a connection between the color of the cloak and the personality.
