Latest news with #HiroyukiSasaki
Yomiuri Shimbun
5 days ago
- Science
- Yomiuri Shimbun
Japan Team: Gene Decides Calico Cat Color Patterns
Courtesy of Hiroyuki Sasaki / Jiji Press A calico cat and Prof. Hiroyuki Sasaki TOKYO (Jiji Press) — A Japanese research team led by Kyushu University Prof. Hiroyuki Sasaki said it has discovered a gene that determines the color patterns of the tricolored calico cat, known in Japan as 'mike neko.' The team found that the coloring was decided by the ARHGAP36 gene on the X chromosome. The orange coloration reflects a missing portion of this gene, while the black fur color is due to the absence of such a deletion, the team said. The team's findings were published in the online edition of the U.S. journal Current Biology on May 15. It was established some 120 years ago that almost all calico cats are female and that the color-deciding factor was in the X chromosomes. About 60 years later, researchers discovered that one of the two X chromosomes is inactivate in calico cats. But the gene responsible for the distinct coloration long remained unidentified. 'As a dog and cat lover, I couldn't let this long-standing mystery go unsolved,' Sasaki said. He said that some of the team's research costs were obtained through crowdfunding between 2022 and 2023, raising over ¥10 million from 600 people. 'I think that there is no doubt (that ARHGAP36 is behind the coloration) as a research team from Stanford University in the United States also identified the same gene and is announcing it at the same time as us,' he said. Sasaki's team, which includes members from Kyushu University, the National Institute of Genetics, Azabu University and Kindai University, extracted and analyzed DNA from cats of many different colors, with the help from an animal hospital in Fukuoka in the Kyushu southwestern region. The team also examined data on cat DNA made available by the University of Missouri before discovering the ARHGAP36 gene. The team said that a deletion of about 5,000 base pairs of the ARHGAP36 gene on the active one of the X chromosomes results in the production of pheomelanin, which is orange in color, while the gene without such a deletion creates the black pigment eumelanin. Courtesy of Hiroyuki Sasaki / Jiji Press A calico cat, left, and a tortoiseshell cat are seen in this combination photo. Like calico cats, tortoiseshell cats, or 'sabi neko,' are mostly female. Tortoiseshell cats also share the same coloring phenomenon. Orange cats are mainly male, possessing one X chromosome and one Y chromosome. Their orange coloration, too, is due to the ARHGAP36 gene deletion on the X chromosome. The rare male calico cats have one extra chromosome, possessing two X chromosomes and one Y chromosome. The white coloration in cats, however, is not the ARHGAP36 gene's doings but is caused by a different gene. Domestic cats are descendants of the African wildcat that were domesticated by about 10,000 years ago. Similar to a brown tabby cat, the African wildcat has brown-black striped fur. The team suggested that it may be able to pinpoint when the ARHGAP36 gene deletion happened by assessing mummies and pictures of ancient cats.
Yahoo
18-05-2025
- Science
- Yahoo
Researchers solve genetic mystery of orange cats
(NewsNation) — Two studies reportedly have solved the genetic mystery behind orange-colored domestic cats. Two independent research teams that published works simultaneously in Current Biology said they have identified the gene mutation that triggers the ginger hue in orange tabby cats. It's a modification, they say, of the gene ARHGAP36 on the X chromosome. Watch: Cat saves dog from attacking coyotes This explains why orange cats are predominantly male. Males have one X chromosome and one Y chromosome, whereas females have two X chromosomes and need two copies of the mutated gene to go completely orange, a less likely scenario. More often, female cats wired with the ginger gene have coats that are patchy calico or a 'tortoiseshell' blend. This comes from having the orange-coloring mutation on one X chromosome and a standard dark-coloring gene on the other X chromosome. 'Identifying the gene has been a longtime dream, so it's a joy to have finally cracked it,' said Professor Hiroyuki Sasaki, a geneticist at Kyushu University in Japan, in a story published by Neuroscience News. A second research team studying the inner workings of orange cats was based at Stanford University. Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Yahoo
17-05-2025
- Science
- Yahoo
Orange cat mystery finally solved after discovery of genetic 'meow-tation'
When you buy through links on our articles, Future and its syndication partners may earn a commission. Orange cats have a unique genetic mutation that gives them their special coats — and this mutation also explains why so many of them are male, two new studies find. Many animals have orange hair, including some humans, but only in domestic cats are males more likely to be orange than females. Researchers have long known there must be something special about ginger cat genetics, and with this newly identified mutation, they've finally solved the mystery. The mutation deletes a section of the cat's DNA, and increases the activity of a gene in X chromosomes — thread-like structures of DNA that carry hereditary information passed on from parent to offspring. In humans and cats, males typically have one X chromosome and one Y chromosome, while females have two X chromosomes. So if male cats have an X chromosome that carries the mutation, then they'll become orange. Female cats, on the other hand, need to inherit the mutation on both of their Xs to be completely orange. Researchers had previously assumed that the mutation would be on the X chromosome because of the skewed sex ratio — it also explains why calico and tortoiseshell cats, which have patches of orange mixed in with black and white, are usually female. In these cases, the cats have inherited one mutated X chromosome. Two research teams, one led by Christopher Kaelin at Stanford University in the U.S. and the other led by Hiroyuki Sasaki at Kyushu University in Japan, independently discovered that the mutation affects a gene called ARHGAP36. The teams shared their findings in separate studies published Thursday (May 15) in the journal Current Biology. "Identifying the gene has been a longtime dream, so it's a joy to have finally cracked it," Sasaki, a geneticist at Kyushu University and self-proclaimed cat-lover, said in a statement released by the university. Related: Cats are better at word association than human babies are, study finds Researchers have been studying cat coat genetics since the beginning of the 20th century, and yet the orange mutation, which the Stanford team called "sex-linked orange," has remained elusive until now. "It's a genetic exception that was noticed over a hundred years ago," Kaelin, a senior scientist in genetics at Stanford University, said in a statement released by the university. "It's really that comparative genetic puzzle that motivated our interest in sex-linked orange." Both research teams discovered the mutation by looking at the DNA of different cats. The Japanese team, which crowdfunded more than $70,000 to conduct the research, found that all of the orange cats they studied shared a mutation, or "meow-tation," that deleted a section of DNA in the ARHGAP36 gene, according to the Kyushu statement. They then examined calico cat tissues and found that ARHGAP36 was more active in the cats' orange patches than in their black or white patches. "This suggests that when present, this section of DNA normally suppresses ARHGAP36 activity," Sasaki said. "When missing, ARHGAP36 stays active." Mammals get their colors from a pigment-producing substance called melanin. Two types of melanin affect coat color: eumelanin, responsible for dark brown and black, and pheomelanin, responsible for yellow, red or orange. In orange fur, the more active ARHGAP36 may drive pigment production towards higher levels of pheomelanin, and ginger fur, according to the Kyushu statement. ARHGAP36 is active throughout the body, including in the brain and hormonal glands, so it's possible the sex-linked orange mutation affects orange cats in other ways, too. Some pet owners swear that orange cats are sillier than other cats, but the Stanford researchers looked at gene expression in the brain and didn't find differences between orange and non-orange cats. Kaelin thinks that their chaotic reputation is more likely due to most orange cats being males — suggesting males are more chaotic — but couldn't rule out ARHGAP36 being a factor, possibly by affecting other tissue in the body. The new study doesn't reveal when the mutation first emerged. However, Kaelin thinks it probably arose early on in the domestication process. RELATED STORIES —Over 40% of pet cats play fetch — but scientists aren't quite sure why —Why do cats bring home dead animals? —The history of cat domestication "We know that because there are paintings that date to the 12th century where you see clear images of calico cats," Kaelin said. "So, the mutation is quite old." Humans first domesticated cats thousands of years ago. To find out whether the mutation goes back millennia, researchers will have to find ancient evidence of orange cats. Sasaki is keen to explore the mutation's origins. "One idea is to study ancient Egyptian cat paintings—or even to test DNA from mummified cats—to see if any cats back then were orange," Sasaki said. "It's ambitious, but I'm excited to try."
Time of India
16-05-2025
- Science
- Time of India
Scientists have finally solved the 100-year-old mystery of why some cats are orange
usually have all eyes on them. Not only because of their silly and chaotic behaviour, but also because of their fur, which is uniquely orange in colour, and the reason for it was an enigma to scientists till now. Tired of too many ads? go ad free now Now, scientists have finally solved the century-old mystery of why some cats are orange in colour. Yes, in two studies published on Thursday, scientists have pointed out the gene that causes the orange cat fur. While one was led by Stanford University's School of Medicine in the United States, the other was led by researchers in Japan. The American study Image credits: Getty Images 'Over the past hundred years or so, it was recognised that orange cats kind of fall outside of the genetic rules for how coat colour in mammals is determined,' said Christopher Kaeline, geneticist at Stanford University's School of Medicine and author of the study. Thus, the investigation into the coat colour of these felines addressed questions about animal evolution and how gene regulation is encoded in the genome. While past studies had pointed to the orange mutation being caused by the X chromosome, by analysing sequencing data, the American scientists mapped the mutation to a DNA deletion near a gene called Arhgap36. The researchers found that cats with the orange mutation expressed higher levels of RNA from the , specifically in the pigment cells. The protein produced by this gene limits a step in the middle of the biological pathway behind the coat colour. In male cats that typically have one chromosome, the orange mutation signals more Arhgap36 protein in pigment cells and activation of a pathway to produce reddish yellow colour. Those that lack the mutation and Arhgap36 pigment cells have the colour black or brown. In females, the coat colour is more complicated as they have two X chromosomes. Tired of too many ads? go ad free now A process known as X-chromosome inactivation turns off one X chromosome in each cell, resulting in a mixed tortoiseshell or calico pattern. The Japanese study Image credits: Getty Images Similar to the American team, the Japanese researchers also identified Arhgap36 as the reason for the orange coat colour. They also confirmed that the gene experiences chemical modifications that suggest it undergoes X-chromosome inactivation. 'The orange gene was a long-standing mystery for scientists,' said study author Hiroyuki Sasaki, a geneticist at Kyushu University's Medical Institute of Bioregulation and Institute for Advanced Study, by email. 'It is a great joy for me to have finally cracked it with my colleagues.' Is the orange mutation responsible for ginger cats being goofy? Image credits: Getty Images It could be right? The orange mutation could be the cause that these ginger cats are way more trouble-causing than other cats, but according to the American team of scientists, it's not so. Potentially, it could be that their friendly demeanour was a by-product of them being typically males, but it could also be caused due to some other genes, as per Leslie Lyons, a feline geneticist at the University of Missouri College of Veterinary Medicine.
The Independent
16-05-2025
- Science
- The Independent
Scientists finally decode what makes orange cats so unique
Scientists have finally narrowed down on a long theorised elusive genetic mutation that makes orange cats so unique, unlike any other mammal. While the orange fur colour can be seen across mammals, including tigers, golden retrievers, orangutans and red-headed humans, only in domestic cats is the colouration linked to sex, appearing much more often in males. This pattern has pointed to an unknown "orange gene" on the X chromosome in cats but identifying this gene has eluded scientists for over a century. Now, a new study published in the journal Current Biology finally unravels this gene, explaining the peculiarity of ginger cat genetics. "Identifying the gene has been a longtime dream, so it's a joy to have finally cracked it," said Hiroyuki Sasaki, a geneticist and co-author of the study from Japan's Kyushu University. Any male cat with the mutation dubbed 'sex-linked orange' will be entirely orange due to a random deletion of a section of its DNA in the X chromosome. However, a female cat needs to inherit the genetic change on both of its X chromosomes to be entirely orange, which makes it a less likely occurrence. If a female cat inherits one orange and one black gene, they develop patchy or mottled coats that is seen in calicos and tortoiseshells. "These ginger and black patches form because, early in development, one X chromosome in each cell is randomly switched off," Dr Sasaki explained. "As cells divide, this creates areas with different active coat colour genes, resulting in distinct patches. The effect is so visual that it has become the textbook example of X-chromosome inactivation,' he said. In the study, researchers analysed DNA from 18 cats – 10 with orange fur and eight without. They found that all orange cats shared a specific deletion in the ARHGAP36 gene, while the non-orange cats did not. Scientists found that this pattern held true in 49 additional cats, including samples from an international cat genome database. However, until the discovery ARHGAP36 gene was thought to have no connection to pigmentation. "ARHGAP36 is essential for development, with many other roles in the body, so I had never imagined it could be the orange gene. Mutations to the protein structure would likely be harmful to the cat,' Dr Sasaki explained. Researchers then found ARHGAP36 gene activity in a cell type, called the pigment cell, in orange cats, where it's not normally expressed. The study found that this rogue expression of the ARHGAP36 gene in the cat pigment cells inhibits an intermediate step controlling coat colour. "Certainly, this is a very unusual mechanism where you get misexpression of a gene in a specific cell type," said Christopher Kaelin, another author of the study from Stanford University. Researchers suspect an altered expression of the gene in some other tissue might also affect behaviour. "There are not many scientific studies of the personality of orange cats," Dr Kaelin said. "For example, many cat owners swear by the idea that different coat colours and patterns are linked with different personalities. There's no scientific evidence for this yet, but it's an intriguing idea and one I'd love to explore further,' Dr Sasaki added. Scientists suspect that one reason orange cats have a reputation as 'friendly agents of chaos' could be due to most of them being male.
