Radio Cadena Agramonte emisiora de Camagüey
Havana, May 17 – Garfield, Puss in Boots, Toulouse from Disney's movie "The Aristocats": cultural icons, perhaps; orange, without a doubt.
Now, scientists from two continents have solved the mystery in the DNA that gives our furry friends, particularly males, their remarkable color.
They discovered that red-haired or orange-colored cats are missing a section of their genetic code, meaning the cells responsible for their fur, eyes, and skin tone produce lighter colors.
The breakthrough has delighted not only scientists but also the thousands of cat lovers who originally funded the research.
Scientists hope that solving the puzzle may also help shed light on whether orange-colored cats are at greater risk for certain health problems.
It has been known for decades that it is genetics that gives orange tabby cats their distinctive tone, but until now scientists could not find the exact location in the genetic code.
Two teams of scientists from Kyushu University in Japan and Stanford University in the US revealed the mystery in simultaneous articles published Thursday.
What the teams discovered was that in the melanocytes—the cells responsible for giving cats their fur, hair follicles, and eye color—of these animals, the ARHGAP36 gene is much more active.
Genes are made up of fragments of DNA that instruct a cat's cells, like those of other living beings, on how to function.
By comparing the DNA of dozens of cats with and without orange fur, they found that those with reddish coloring had a section of DNA code missing from this ARHGAP36 gene.
Without this DNA, ARHGAP36 activity increases. Scientists believe the gene instructs these melanocytes to produce a lighter pigment.
Mostly male
For decades, scientists have observed that cats with completely reddish coloration are much more likely to be male. This coincides with the fact that the gene is located on the X chromosome.
Chromosomes are larger sections of DNA, and male cats, like other mammals, have one X and one Y chromosome, which contain different amounts of genes.
Since this is a gene found only on the X chromosome, which in this case controls pigment production, a missing DNA fragment is enough for a cat to become completely red-haired.
In comparison, female cats have two X chromosomes, so DNA loss on both chromosomes would be necessary to increase the production of lighter pigments to the same extent, meaning that mixed coloration is more likely.
"These reddish and black shapes are due to the fact that, early in development, one X chromosome in each cell is randomly exchanged," explains Professor Hiroyuki Sasaki, a geneticist at Kyushu University.
"As cells divide, areas with different active coat color genes are created, resulting in distinctive patches."
Scientific curiosity
Although the study is based on scientific principles, it originally began as a passion project for Professor Sasaki.
He had retired from his university position, but as a cat lover, he said he wanted to continue working to discover the orange cat gene in the hope that it could "contribute to overcoming feline diseases."
He and his team raised 10.6 million yen (US$73,000) from thousands of cat lovers in Japan and around the world through crowdfunding to conduct the study.
One of the contributors wrote: "We are brothers and we attend first and third grade of elementary school. We donate our pocket money. Use it to research calico cats".
The ARHGAP36 gene is also active in many other areas of the body, including the brain and hormone glands, and is believed to be important for development.
Researchers believe it's possible that the DNA mutation in the gene could cause other changes in these body parts linked to health conditions or temperament.
The ARHGAP36 gene is found in humans and has been linked to skin cancer and hair loss.
"Many cat owners are carried away by the idea that different colors and fur patterns are linked to different personalities," said Professor Sasaki.
"There is no scientific evidence to support this yet, but it's an intriguing idea, and I would love to explore it further." (Text and Photo: Cubadebate)
