Will crossing a sphynx cat with a fluffy cat breed result in hairless or fluffy kittens? this article will simplify the complicated genetics of hairless cats to answer this question. Bottom line: yes, your purebred sphynx queen can give birth to furry kittens if the other parent is a furry breed.
If a sphynx cat is crossed with a furry cat that is heterozygous for the recessive hairless gene, about half of the offspring will be hairless. if a sphynx cat is crossed with a fluffy cat that is homozygous for the dominant fluffy gene, all the offspring will have fluffy fur; however, crossing the offspring of the aforementioned cross with a sphinx will again result in 50% hairless offspring.
This is not to say that a sphynx queen will give birth to a fluffy kitten (or more) if she mates with a tom cat that is a furry breed. nor is it to say that a sphynx queen will give birth to only hairless kittens if she mates with a furry cat. this matter, unsurprisingly, has variable results and depends mostly on the complicated (or simple, depending on how you find it) subject of genetics.
This all may sound very complicated, but wait. it will all make sense by the end of this article! First, we need to start by explaining the basics of genes for the hairless trait.
why doesn’t a sphinx have hair?
At the core of the unique characteristics of all animals (and humans) is, of course, the genetic code that comprises DNA. we all know that within this encoding, there is a certain level of variation that makes every living thing on this planet different from other species and also different within species.
Sphynx cats are a well-known genetic marvel among domestic cats and an interesting display of Mendelian inheritance when it comes to genetic principles. how come they are hairless mammals?
origins of the sphynx cat
The first hairless kitten was documented in Toronto, Canada, in 1966, one of a litter of two domestic shorthair cats, thus originally known as the Canadian Hairless breed (Murphy, 2022). Over the years the hairless trait was selected for by crossing those cats with other furry breeds in the hopes of obtaining naked kittens and then crossing hairless with hairless.
These hairless cats were also, at one time, bred with the Devon rex, a breed of cat that has sparse, curly hair. this was done in order to increase the number of hairless kittens born to develop the sphynx breed. Today, the sphynx is a renowned anomalous nude pet that is growing in popularity.
for the sake of simplicity, we won’t delve into how Devon rex genetics helped develop a hairless cat breed, but if you find this interesting, take a look at the article by gandolfi et al. (2010) for more information.
let’s talk about basic genetics
Early, the genetic inheritance of the hairless trait was identified as taking the form of an autosomal recessive gene given the symbol h (Robinson, 1973). autosomal means that the gene is found on chromosomes other than the gender-determining chromosomes, and therefore the trait has no predilection for males over females or vice versa. recessive, which means that the trait is only expressed in the phenotype (outward appearance) if there is no dominant partner present at the specific locus on a chromosome.
according to the national human genome research institute, the definition of a single nucleotide polymorphism (snp) is a genomic variant at a single base position in DNA (gunter, 2022). this snp creates a variation called an allele. Simply put, alleles are different forms of a gene at a locus on a chromosome and are the determinants of distinction & dissimilarity between organisms of a species.
the naked trait of sphynx cats is due to a snp in the keratin 71 (krt71) gene. most sphynx cats are either homozygous for the hr allele at the hairless (h) locus, or compound heterozygous with the re allele at the rex (r) locus for curly-haired devon-rex, indicating that these are allelic and that the sphynx allele is dominant, the sphynx mutation results in hair still being produced, but falling out very easily due to malformed bulb (gandolfi et al., 2010).
tip for pet veterinarians: for more information on the specific skin characteristics of sphynx cats and how to care for the skin of this special breed, see the article on skin conditions of sphynx cats.
what happens if you cross a sphynx cat with a fluffy cat?
let’s play with some genetics. we’ll ignore the role of them rex locus (of the devon rex breed) for now to keep it simple. Remember that a kitten, like all creatures that possess DNA, receives an allele from its mother & an allele from his father.
- hr denotes the recessive hairless allele encoding hairlessness.
- hr denotes the dominant allele encoding hair. if this allele is present, even if there is only one, dominance dictates that the cat will have hair.
- gandolfi, b., outer bridge, c. a., beresford, l. g., myers, j. A., Pimentel, M., Alhaddad, H., Grahn, J. c., grahn, r. a. & lions, l. a. 2010. The Naked Truth: Mutations of Sphynx and Devon Rex Cat Breeds in Krt71. Mammalian Genome, 21, 509-515.
- gunter, c. 2022. National Human Genome Research Institute, Single Nucleotide Polymorphisms
- Murphy, L. 2022. sphynx: cat breed profile, characteristics & watch out
- Robinson, R. or and. 1973. The Canadian Hairless or Sphynx Cat. heritage magazine, 64, 47-49.
See Table 1 to see how the composition of the alleles at the h locus determines the physical appearance of the cat.
table 1:
To understand the inheritance of the hairless trait, take a look at the following examples that demonstrate the result of breeding sphynx cats to a hairy or other sphynx breed.
example 1: a sphynx cat with the hrhr genotype is crossed with a domestic shorthair cat with the hrhr genotype.
all of the pups, in this case, have the hrhr genotype, which means they will have the dominant gene for fur, and therefore will all be fluffy kittens.
example 2: a sphynx cat with the hrhr genotype is crossed with a domestic shorthair cat with the hrhr genotype.
50% of the offspring, in this case, will be hrhr, meaning they will have hair, and 50% will have the hrhr genotype, resulting in hairless (sphynx) kittens.
example 3: two sphynx cats with the hrhr genotype are crossed.
in this purebred match, all the kitties will be hairless & therefore, sphynx cats as there is no dominant (hr) allele present at all.
From the examples above, it’s clear that a sphynx queen can give birth to furry kittens if the male cat is a furry breed. since the furry gene is dominant, even if the cat has only one hr allele, the offspring will still have a 50/50 chance of being furry. therefore, if you bred your sphynx queen to a furry male, theoretically at least 50% of the offspring would be furry.
There’s hardly a queen giving birth to enough pups in a litter for you to see a 50/50 split every time, and as with all things biological, you may not see a single fluffy kitten in the litter, or you may just see a fluffy kitty in the litter! however, this is still the simplified answer to the question that a sphynx can produce fur-bearing offspring.
