Calico cats are lovely and unique. Even more unique is the fact that they are nearly always female. I can take advantage of my knowledge of this to impress my clients by correctly guessing the gender of their cat from a distance! Although it can make me seem magical, science makes my skill much less impressive. Why are male calico so rare? To answer this question, we have to first examine what calico is and why any cat has this interesting coat color. The word “calico” can refer to a printed fabric (as in a calico cotton dress), but the term is now most commonly associated with cats. A calico cat will have areas of black, white, and orange scattered all over her body. Usually the cat’s body is mostly white and the other two colors disperse across them in large and small patches.  The patches are actually the visual expression of the cat’s DNA. You see, the colors are coded on the cat’s gene map. But it just so happens that each of these colors are coded on the X chromosome. In a female cat, who has XX pairs, the orange-expressing X shows in some areas and the black-coded X shows in others. In a male cat, who has only one X chromosome, the two colors are not able to express in this way. In fact, in order for a male cat to even carry and express both of these colors, he must have a genetic rarity known as Klinefelter syndrome. Klinefelter males have an extra X chromosome, so their genetic map is XXY. Because of the presence of the two X chromosomes, Klinefelter males can appear calico. Klinefelter syndrome is named after the doctor who first described it in humans. It a rare genetic defect in human beings, only occurring at a rate of 0.2%1, but it is likely even less common for cats. If you have a calico male cat, he is very rare indeed. But sadly, these cats are usually sterile so this trait cannot be purposefully selected for. If you have a female calico, she is also a unique and interesting visual reminder of how complex and beautiful genetics can be! Do you love learning about cats? I love sharing about them. Learn more by finding me on Facebook by clicking here.
Thursday, Sep 8th, 2016 | By Dr. Marty Becker
Few questions fascinate the pet-loving public as much as why there are (almost) no male calico cats. Here’s what a recent reader asked, and my answer: Q: Why is it so unusual for male cats to be calicos? A: I’m glad you asked. Feline color genetics is always a fascinating topic. To get started, let’s define our terms. A tortoiseshell cat has patches of orange or red and patches of black, chocolate or cinnamon. When those patches are combined with a white background, the cat is called a calico, after a type of colorful patterned fabric. A study done by researchers at the College of Veterinary Medicine at the University of Missouri found that only 1 of every 3,000 calico cats is male. That’s because the gene that determines how the orange color in cats displays is on the X chromosome, one of the two chromosomes that determines gender. Females have two X chromosomes, while males have an X and a Y chromosome. While any cat, male or female, can be orange, in males the orange almost always occurs in the tabby pattern. Females can be orange tabby, calico or tortoiseshell. In rare instances, though, a male cat turns up with not only his allotted X and Y chromosomes, but also an additional X chromosome. If both of those X chromosomes happen to carry the gene for orange coloration, bingo: You have a calico male. This genetic anomaly is called Klinefelter syndrome, after the doctor who identified it in the 1940s. In human and feline males, it typically causes sterility, which is one reason you don’t see people getting rich off breeding their rare male calico cats. Interestingly, the source for calico coloration was traced in the 1970s by Neil Todd, who was studying the migration routes of domestic cats. The orange mutant gene that causes the patched appearance originated in Egypt and then spread to Mediterranean port cities in Greece, Italy, France and Spain. Read more, including how to care for your long-haired pets, in this week’s Pet Connection! Cat owners and enthusiasts have heard a number of fascinating myths about male calico cats. While they are relatively rare, with an estimated one male in 3,000 calico cat births, there is no extraordinary demand for them. They do not make good breeding studs because almost all male calicos are sterile. In fact, only about one in 10,000 male calicos is fertile.
Unlike cats with tortoiseshell coloring, the coats of calico cats are of three distinct colors - red, black, and white, or a variation of those colors.
Male calicos are a genetic anomaly. Cats, like humans, have two sex chromosomes. Chromosomes carry genes and determine an animal's traits. The required red color for a calico cat is passed only on a female (X) chromosome. How, then, can a male cat inherit the red coloring required for a calico cat?
To put it simply, two chromosomes determine gender. Each parent contributes one chromosome to the offspring. The mother, who has only X chromosomes, always contributes an X chromosome. The father, who has both X and Y chromosomes, can contribute either an X or a Y chromosome to his offspring. Thus, it is the father who determines the sexes of his kittens. The red color gene cannot be passed to a male offspring due to unusual characteristics of the gene in question. Under certain conditions, when the red genes are passed to a female offspring, she displays not the expected red or orange coat but the tricolor coat of a true calico cat.
How, then, can a male be a true calico? Sometimes there is an incomplete division of the chromosome pair when the chromosomes are separating at the time of fertilization. When that happens, the incomplete chromosome ends up attached to another of the two required chromosomes, giving the offspring one of the following combinations:
In both cases, the result is a male cat who can inherit the trait for a true calico coat. Among humans, this genetic arrangement is called Klinefelter syndrome. A male calico usually cannot sire offspring because the genetics described above almost always guarantee he will be sterile.
One might suppose that male calicos would bring a high price among breeders because of their rarity. You may even see some websites claiming a purebred male calico cat can fetch a price as high as $1,000 to $2,000. The truth is, while they are an interesting phenomenon, they are of little interest to breeders because they are sterile. It's possible a pet owner might want to pay that amount of money to own a cat that's a rarity, but chances are if you're looking to buy a male calico cat, don't expect to pay much more than you would for any regular unpedigreed house cat.
Male calico cats are the offspring with a genetic anomaly of parents representing many possible cat breeds. While female calico cats are quite common, true male calicos are rare and of particular interest for the combination of their unique coloration and sex. While it's a myth that they can command a high price among cat fanciers, if you happen to own a male calico, you can treasure him for his rare condition and other wonderful feline attributes! © 2022 LoveToKnow Media. All rights reserved. |
Why are male calico cats rare
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