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A new study may have revealed exactly what Orange Cats is doing special – although it may not be because of the reason you think.
Ginger kittens are known among cat owners for being particularly friendly and enchanting. For genetics, however, the uniqueness of these domestic cats comes from the unusual way they get their color. Scientists now say that they have solved a long -standing mystery by identifying the specific DNA mutation responsible for this golden tint – and the option was not found in any other animal.
The genetic version was first described in a document published on May 15 at Current Biology.
“This is a really unusual type of mutation,” says leading study, Christopher Kaelin, a senior genetics scientist at Stanford University in California.
The greater part of the completely orange cats are men, which made scientists think decades ago that the genetic orange code is transferred to the X chromosome. As with other mammals, female cats have two x chromosomes, while men have one X and one Y. Every male cat carrying the orange feature of their X chromosome will be entirely orange. A woman will have to inherit the line of both X chromosomes (one of each of her parents) to be completely orange, which makes it less likely. Instead, most female cats with orange coat have spots of models – calico or turtle – which can include black and white.
But when the mutation exists on the X chromosome and how it causes orange coloring, it has been enigma so far. Usually, mutations that lead to yellow or orange coat in animals (and red hair in humans) occur in genes that control color. And these genes are not worn on the X chromosome. “This has suggested that by identifying the molecular cause we can learn something new and interesting that turned out to be so,” says senior study author Greg Bard, professor of genetics and pediatrics in Stanford.
The findings not only clarified the special origin of the charismatic color of some cats, but also revealed new insights to a well -known gene.
Genetic problem behind orange cats
Female cats carrying the genetic code for the orange color of one X chromosome will not be ginger. They will be turtles (left) or calico. – Laurie Laporte/Moment RF/Getty Images
Scientists have long known about this gender mutation; The mutation itself puzzled the geneticists. – Ping Shu/Moment RF/Getty Images
The first step was to identify genetic mutations that are unique to orange cats and can lead to their color. For a decade, Kaelin has been visiting cat shows, asking owners of ginger -colored cats if he can take the animal’s DNA samples with a cheeks tampon. (He is also interested in models that are similar to those found in wild cats such as leopards and oceans, which are common in popular breeds such as Bengal cats and toys.)
Comparing his DNA collection to cat genomes that have been secked in the last five to 10 years, he and his research team have discovered 51 genetic variants of the X chromosomes that have been shared by orange men. But 48 were also found in non-orange cats, which left three likely candidates for the elusive mutation.
One was a small deletion of a 5.076 base, which removed about 0.005% of the X chromosome in a region that does not seem to encode a certain protein. The deletion was not located within a gene where mutations are usually found. However, the mutation lies between two places related to the nearby gene called Arhgap36, which regulates an important hormonal signal path used by almost all cells and tissues of mammals. There was no some connection with pigmentation. The gene is not even included in the pigment cells.
To understand how the gene affects the color, Kaelin examines its actions in live tissues gathered in Spray and neutral clinics, which would otherwise be thrown away. Experiments have shown that somehow deletion activates Arhgap36 in the pigment cells, where it blocks the production of black pigment so that the cells produce orange.
The variant was not found in other animals, including wild cats that gave rise to domestic cats.
“This is a genetic exception that was noticed more than a hundred years ago,” Kaelin said in a Stanford University News. “This is really a comparative genetic puzzle that motivates our interest in orange orange sex.”
This singularity suggests that the mutation probably occurred once during domesticating and was then selectively raised, Kaelin said. “We see the same mutation in all the orange cats that we looked at over a wide geographical area, so there is a single mutation that happened,” he said. “And we know that the mutation is quite old because there are images of Calico cats in Chinese art that dates from the 12th century.” He added that prehistoric DNA specialists can be able to use new discoveries to determine when and where the mutation originally originated.
“The identified options can serve as valuable tools in population genetics to track the home evolutionary history of cats,” says Hannes Lohi, a professor of veterinary biological sciences and genetics at the University of Helsinki in Finland. Lohi did not participate in the study.
Meanwhile, Kaelin and his associates want to understand how a small deletion, which is not within a gene, can change the activity of a nearby gene.
“The goal is, we will probably learn about the mutation,” noted Brash, “But we also want to learn more about mutational mechanisms in general: why is it so unusual and the same mechanism can happen in other genes that cause other phenotypes in other animals?” He pointed out that there are many conditions in humans that are thought to be genetic but for which a genetic mutation has not been identified. Perhaps, he claims, the problem is not simply that we have not found mutations, but that we do not understand all the ways in which mutations can cause traits of the disease in the first place.
And can the unusual genetics of Orange Cats possibly explain their specific personalities? So far, Kaelin has said that he and his colleagues have no reason to think so, although other researchers could take advantage of the findings of a new study to seek associations between behavior and coverage color. “I think the orange cats have really convinced their owners that they are different, but they are yet to persuade us,” he said.
Amanda Schupac is a scientific and health journalist in New York.
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