Summary:
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The genetic mystery of orange cats as males was finally solved by a groundbreaking study at Stanford Medicine.
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A small X chromosome deletion in the ARHGAP36 gene is the unique cause of orange coloration in cats.
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Approximately 80% of orange cats are male due to the X chromosome, a discovery that shocked scientists.
The mystery about the dominance of orange cats as males flourished over a century as scientists struggled to understand the phenomenon. Finally, a revolutionary study at Stanford Medicine in 2025 has broken the genetic code of that beloved ginger coat – and the answer to the question shocked everybody.
Key Discovery
A small X chromosome deletion in the ARHGAP36 gene is the only cause that makes domestic cats turn orange – a mutation that has not been observed in any other mammal on the planet.
Best Mystery Of All Time That Labored The Scientists
The reason behind the orange coloration of cat coats has been a puzzle to scientists since the early 1900s, yet the genetics of the cat coats has not been a puzzle because of the coloration of orange cats.
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The Reason Why Most Orange Cats Are Male
You are not alone in thinking that most orange cats appear to be boys. NPR establishes that approximately 80 percent of all the orange cats are male, and the skewed proportion led the scientists directly to the X chromosome.
The Stanford Medicine Breakthrough That Changed It All
In May 2025, a Stanford Medicine group headed by Christopher Kaelin reported in Current Biology the precise DNA deletion underlying the iconic ginger coat.
ARHGAP36 Gene: The Surprising Cat-Color Gene
Stanford Medicine found that a tiny deletion of the DNA causes the ARHGAP36 gene to become active 13 times in pigment cells, turning the color of these cells to orange rather than brown-black.
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Why So Few Female Orange Cats?
The color of a female cat is determined by two X chromosomes. To be completely orange, the genetic mutation of being orange should be present in both X chromosomes, and this is a very rare phenomenon in cats. Thus, an orange female cat at your local shelter is a unique find.
The Technology Of Calico And Tortoiseshell Coats
Calico and tortoiseshell cats with patchwork coats: The orange mutation is present in only one of the X chromosomes of the female. X inactivation is random, silencing one X in each cell, generating the mosaic effect.
The Same Finding Was Confirmed By Two Independent Research Teams
An independent study by Kyushu University in Japan had the same conclusion. The ARHGAP36 deletion in hundreds of world cat genomes was confirmed by both teams on May 15, 2025, in Current Biology.
Mutation Unique To Domestic Cats Only
Orange hues are shared by tigers, golden retrievers, and orangutans as a result of varying genes. Science News describes that the ARHGAP36 mutation is only present in domestic house cats.
The Evolutionary History Of This Cat Gene Mutation
Scientists date the mutation in cat DNA to more than 900 years ago, to the time of domestication. In 12th-century art, Calico cats were found, meaning that your orange tabby had a very ancient genotype.
What The Discovery Has The Potential To Do To Human Health Research
Phys.org reported that ARHGAP36 is present in humans and is associated with skin cancer and hair loss. The results of the study of the coat color of a ginger cat have possible far-reaching implications.
