Your Cat Has a Gene No Wild Cat Has. How Domestication Rewired Feline Speech

Though it sounds like science fiction, these are the hard conclusions of a study by a team from Kyoto University in Japan, published in May 2025 in the scientific journal PLOS ONE. What's more, these newly arisen genetic variants produce a measurable behavioural effect. Domestic cats that carry them are less sensitive to hormones, so they purr less often and are gentler. Cats in which the older, evolutionarily primal versions of the gene survived (the same ones wild cats carry) show a stronger hormonal response — they purr far more often and are more strongly territorial.

This is the very first study of its kind to prove that roughly nine thousand years of evolution alongside humans permanently modified the cat gene responsible for the body's response to its own hormones. From a scientific standpoint it's a fascinating slice of molecular biology. For you, as an owner, it's a ready answer to the nagging question of why your companion so rarely vibrates on your lap.

The key discovery — the 2025 study

The Japanese researchers' work is a breakthrough moment: for the first time in the scientific literature, a specific polymorphism (a natural variation of a gene) was linked with the behaviour of a domestic cat. Initially 441 animals were behaviourally assessed, and the results of 280 of them (145 males and 135 females) qualified for detailed statistical analysis. Almost all the cats studied had been neutered or spayed, and 86 percent of the group were common mixed breeds. Their genetic sequences were set against databases for eleven wild species of the cat family (Felidae).

The scientists focused on the gene coding for the androgen receptor (AR), located on the X chromosome. This receptor is a specific cellular protein that, like an antenna, catches testosterone and translates its signal into switching genes on or off in target tissues, including the brain. At one end of this gene lies a special segment called the CAG stretch. It is made of repeating DNA building blocks (cytosine-adenine-guanine). In domestic cats, the number of these repeats ranges from 15 to 22.

20–22

The alleles of the androgen receptor gene that respond most weakly to hormones — the 'quietened' ones — arose only in domestic cats.

The principle is simple: the shorter the stretch (fewer CAG repeats), the more strongly the receptor responds to testosterone. It was established that the so-called short type (18 repeats or fewer) is more sensitive to hormones, while the long type (19 or more) shows a weaker, muted response. By far the most common variant in today's domestic cat population turned out to be the extended one, with 19 repeats. In terms of feline behaviour, the results fell into a strikingly clear pattern:

• Both males and females carrying the short allele (the more hormone-sensitive version) purred noticeably more often.
• Males with the short variant showed markedly more human-directed vocal behaviour.
• Females with the short variant showed markedly higher aggression toward unfamiliar people.

The same sensitive genetic variant therefore produces a different effect depending on the animal's sex — males become more communicative, while females more strongly defend their territory.

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An evolutionary novelty found only in domestic cats

The real revolution in this research comes when the results are set against the wild. The team checked how the described fragment of the gene looks in wild felines. The great roaring cats — tigers, lions and leopards — have very short versions, with 12 to 13 CAG repeats. Lynxes and Asian leopard cats have 15. Cheetahs and African wildcats (from which our domestic cat descends directly) carry a variant with 19 repeats.

The startling conclusion: the long alleles with 20, 21 and 22 repeats occur in absolutely no wild species covered by the study. In other words, the new genes with the weakest response to male sex hormones arose only in domestic cats. It is a biological innovation brought about by thousands of years of domestication.

How do the study's authors explain it? In the natural environment, a loudly vocal, territorial predator with a strong androgen response (the one with the short, old version of the gene) has an enormous advantage — it more easily attracts mates and more effectively defends precious resources. The situation reverses completely near human settlements. A cat that responds more weakly to testosterone (the one with the long, new version of the gene) becomes less territorial, gentler and vocalises less, which makes coexistence with humans easier. It doesn't have to shout to survive, because it is fed regularly. Over the millennia, nature unwittingly selected and promoted cats with a quietened hormonal profile — right up to the emergence of genes entirely foreign to the wild.

The chemistry of the androgen receptor

To understand the phenomenon of behavioural differences better, let's look at it from the level of cellular chemistry. When a molecule of testosterone (or its stronger derivative) penetrates a cat's cell, it immediately binds to the androgen receptor protein. The activated complex heads for the cell nucleus, where it binds to the DNA strand, switching gene activity on or off, including in the brain.

The CAG segment at the end of the receptor directly determines how strongly this coupled system will act on the nucleic acid. The shorter the repeat sequence, the stronger the transmitted signal and the more abrupt the change it produces in tissues. Interestingly, this effect is seen even in neutered animals. Even at dramatically low testosterone levels, a receptor with the short gene variant still effectively catches weaker androgens secreted, for instance, by the adrenal cortex, driving the cat toward constant communication with its surroundings.

Cat domestication from a scientific perspective

To fully appreciate this phenomenon, we must place it in history. Ancient-DNA studies confirmed that cats drew close to us in two great waves. The first took place in the Near East about nine thousand years ago, when grain stored by farmers attracted rodents, and the rodents in turn attracted wild cats. The second wave came four thousand years ago in ancient Egypt, from where cats spread across the whole Mediterranean basin aboard merchant ships.

Advanced whole-genome analyses revealed clear signs of evolutionary selection. They concern sequences linked with memory processes, the brain's reward system and the functioning of specific neural crest cells. These cells play a leading role in the scientific concept known as the domestication syndrome. According to it, the classic attributes of tamed animals — floppy ears, patched coats, a shortened muzzle and a lowered fear threshold — result from a slowing of these cells' development at an early embryonic stage.

In many respects domestic cats still perfectly mimic predators; their size and body proportions, including the brain, have changed only slightly, which is why they are often called only partially domesticated animals. The 2025 discovery of novel, quietening alleles in the androgen receptor gene is evidence that fits the theory perfectly — one in which humans simply favoured gentle individuals around them. Our domestic predators were not deliberately, methodically bred (as in the famous silver fox domestication experiment); rather, the centuries-long pressure of living in a human environment shaped them on its own.

What it means for you and your cat

Why does your cat rarely purr? Rest assured: it is most likely not a sign of a lack of trust, love or hidden illness. It may simply be a matter of carrying the long, 'modern' variant of the gene (20 to 22 repeats), which arose during evolution alongside humans and made the animal resistant to the strong action of hormones. Breed also plays an important role here. Representatives of particular breeds — Persians, Maine Coons or Ragdolls, for example — are by nature very low in their need to make sounds. Unfortunately, at present (given the state of knowledge and technology in 2026), the genetic tests commercially available at vets do not measure the length of this specific gene fragment, so we can't confirm it in the clinic.

What if the cat purrs non-stop? This strongly suggests its X chromosome retained the old, short and highly hormone-reactive version of the gene, known from the wild. Before you chalk it all up to genetics and innate hormone reactivity, though, I strongly advise always ruling out potential medical problems with your vet first. Unexpected vocalising can result from severe pain, secretory disturbances in hyperthyroidism, problems with progressive deafness (when a cat cries loudly, not hearing its own voice), or spatial confusion in elderly cats suffering from dementia. Once you've had your companion examined and ruled out clinical problems, accept its chatty nature calmly. It is simply biology in its purest form — the receptors in your cat's body catch hormones more strongly, which chemically drives its innate need for constant vocal communication.

Why is a female cat sometimes aggressive toward guests? As modern analyses prove, females with the short version of the gene respond far more strongly to the androgens naturally present in their bodies. This chemical sensitivity directly stimulates the brain's vigilance centres, which translates into a reinforced, innate instinct to defend territory against intruders. It isn't that the animal is simply being nasty — this is what her hormones dictate. It's worth approaching this with understanding and working on gentle, gradual socialisation based on positive stimuli. Synthetic anxiety-easing pheromones work well. Above all, though, let's not force such a female into physical contact.

Is DNA, then, an unambiguous verdict? Of course not. A single gene's traits can explain only a microscopic part of the variation in an animal's character. Huge studies on samples of thousands of cats have proved conclusively that heritability of behavioural phenomena hovers within just 40 to 53 percent. Comparable publications from the dog world show that breed membership accounts for no more than 9 percent of an animal's actual disposition. Half of the outcome is always environment, our upbringing, unique life experiences and acquired knowledge. Genetics does not decide definitively; it defines the pool of mathematical probability we must work with day to day.

Summary — what it means for owners

Thanks to the latest scientific literature, we know for certain that the polymorphism of the androgen receptor segment casts entirely new light on feline purring and the level of territorial behaviour. Cats with a short sequence in this receptor show a stronger response to hormones, so they enter into sound-vibrations far more often and defend their territory more fiercely. The long genes (which condition a muted response to testosterone), by contrast, exist nowhere in the kingdom of wild fauna — they evolved in domestic cats solely as a tool to ease coexistence with modern human society.

Next time you hear the contented vibrating sounds of a companion nestled on your lap, treat it as a fascinating, living proof of evolution. Physically, that purr resembles the signals of the primal wildcat of nine thousand years ago, yet the cellular mechanism triggering the process now bears the signature of millennia of our shared taming. The genetic changes touched not only the colour, size or head shape of our cats. Deep at the level of proteins, they also modified the way they choose to talk to us.

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References

1. Okamoto, Y., Hattori, M. & Inoue-Murayama, M. (2025). Association between androgen receptor gene and behavioral traits in cats (Felis catus), PLOS ONE, 20(5), e0324055doi:10.1371/journal.pone.0324055
2. Ottoni, C., Van Neer, W., De Cupere, B. et al. (2017). The palaeogenetics of cat dispersal in the ancient world, Nature Ecology & Evolution, 1, 0139doi:10.1038/s41559-017-0139
3. Montague, M.J. et al. (2014). Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication, PNAS, 111(48), 17230–17235doi:10.1073/pnas.1410083111
4. Wilkins, A.S., Wrangham, R.W. & Fitch, W.T. (2014). The 'domestication syndrome' in mammals: a unified explanation based on neural crest cell behavior and genetics, Genetics, 197(3), 795–808doi:10.1534/genetics.114.165423
5. Driscoll, C.A., Macdonald, D.W. & O'Brien, S.J. (2009). From wild animals to domestic pets, an evolutionary view of domestication, PNAS, 106(Suppl 1), 9971–9978doi:10.1073/pnas.0901586106
6. Salonen, M. et al. (2019). Breed differences of heritable behaviour traits in cats, Scientific Reports, 9, 7949doi:10.1038/s41598-019-44324-x
7. Konno, A. et al. (2011). Androgen receptor gene polymorphisms are associated with aggression in Japanese Akita Inu, Biology Letters, 7(5), 658–660doi:10.1098/rsbl.2011.0087
8. Duffy, D.L., de Moura, R.T.D. & Serpell, J.A. (2017). Development and evaluation of the Fe-BARQ: a new survey instrument for measuring behavior in domestic cats, Behavioural Processes, 141, 329–341doi:10.1016/j.beproc.2017.02.010
9. Hart, B.L. & Hart, L.A. (2013). Your Ideal Cat: Insights into Breed and Gender Differences in Cat Behavior, Purdue University Press
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11. Morrill, K. et al. (2022). Ancestry-inclusive dog genomics challenges popular breed stereotypes, Science, 376(6592), eabk0639doi:10.1126/science.abk0639
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Frequently asked

Why does my cat hardly ever purr?

Most likely it isn't a lack of trust or love, but biology. It may carry the long, 'modern' variant of the androgen receptor gene (20–22 CAG repeats), which arose during evolution alongside humans and dampens the body's response to hormones. Breed matters too — Persians, Maine Coons and Ragdolls are naturally not very 'talkative'. Note: commercial genetic tests (as of 2026) do not measure the length of this stretch, so you can't confirm it at the clinic.

Why does my cat meow and purr non-stop?

This suggests its X chromosome kept the old, short, highly hormone-reactive version of the gene, the one known from the wild. Before you pin everything on genes, though, always first rule out medical causes with your vet: pain, hyperthyroidism, progressive deafness, or dementia in an older cat. Once the cat has been checked and is healthy, you can simply accept its chatty nature calmly — it's biology, not a whim.

What is the CAG stretch and the androgen receptor?

The androgen receptor (AR) is a protein that, like an antenna, catches testosterone and translates its signal into switching genes on or off, including in the brain. At the end of the AR gene sits the CAG stretch — a repeating segment of DNA. In domestic cats it ranges from 15 to 22 repeats. The shorter it is, the more strongly the receptor responds to testosterone — hence a stronger drive to vocalise and defend territory.

Do genes decide a cat's character?

Only partly. A single gene's traits explain a small slice of temperament variation. Large studies show that heritability of behavioural traits in cats falls within 40–53%, while in dogs breed alone accounts for no more than about 9% of disposition. Half of character is environment, upbringing and individual experience. Genetics sets the pool of probability, not the verdict.

Why are some female cats aggressive toward guests?

Females with the short version of the AR gene respond more strongly to naturally occurring androgens, which stimulates the brain's vigilance centres and reinforces the innate instinct to defend territory. It isn't 'meanness' — it's chemistry. It's worth approaching this with understanding: work on gentle, gradual socialisation with positive stimuli, support it with synthetic calming pheromones, and never force the cat into contact.