Post by DOG on Jun 5, 2008 19:04:23 GMT -5
Tortoiseshells, Calicos Torbies, and Calibys - oh my!
by M.Kohler.
Wait, what on earth is a tortoiseshell? Torbie? What are you talking about?
I won't bore you with the technical terms , but basically tortoiseshell is a name for a coat coloration in cats, where a shade of black or gray, and a shade of ginger (orange or red) both exist on the cat to form a unique pattern. The name "tortoiseshell" refers to cats that have little to no white markings, and whose coat is a mix of black and ginger.
Cats that have a significant amount of white in addition to the black and ginger are referred to as tortoiseshell-and-white, or as "calicos" in the United States. As the books are set in the United Kingdom, the term "calico" does not come up in the books.
Calicos and tortoiseshells may also come in "dilute" form. When dilution genes are present, the color is modified so that the black appears as gray or grayblue, and the ginger as a lighter cream or fawn.
Ahh, I see! But, what are torbies and calibys?
Torbies are cats that have tabby markings, with the addition of cream or ginger/orange markings. The dilution gene can also occur in these, causing the cat to be a lighter gray tabby with the presence of a lighter ginger or cream. Cats with torbie markings and white, are called torbie and white, or "calibys". The latter term is not used as often as the former.
It is also possible for pointed cats (i.e. "Siamese" or "Snowshoe" types) to have torbie and tortie points.
Hey, those sound pretty cool! I'm going to make a calico tom right now!
Whoa there, not so fast! In cats, calicos and tortoiseshells are almost always female; male calicos and tortoiseshells are extremely rare.
What?! I want to make my tom a calico! Why can't I?!
To answer this question, one must look at the genetics of color, and genetics in general.
As many of you probably remember from basic biology, gender in mammals is determined by two chromosomes, known as X and Y chromosomes. Females possess two X chromosomes (XX), while males possess one X and one Y (XY).
...what's a chromosome?
To explain what a chromosome is, let's summarize what the term "DNA" means. DNA, which stands for Deoxyribonucleic acid, is basically the genetic blueprint that contains instructions for development and function in living things. All living things with the exception of certain viruses, are made up of DNA.
DNA can be -very- complicated to explain, and confusing to figure out, so I'm not going to hurt your head with complex and difficult terms.
...*blank stare*...
Don't zone out on me yet! It gets easier to understand from here.
A chromosome is a long, continuous piece of DNA organized in a cell , and contains many genes.
Genes contain information that contributes to inheritance of behavioral and physical traits.
Genes that are located on either the X or the Y chromosomes are referred to as "sex-linked" genes, while genes on chromosomes other than the X and the Y are referred to as "autosomal" genes.
Below is an image of a "karyotype", which is a collection of chromosomes that make up mammals. This particular karyotype is a human male, as noted by the "XY" chromosomes seen on the very bottom right of the image.
As you can see, the Y chromosome is much smaller than the X chromosomes, and therefore contains less genes than the X chromosome does. Genes carried on the X chromosomes vary between species, and abnormal forms of these genes can result in genetic disorders.
In cats, one gene out of several that control fur color is located on the X chromosome. There are two forms of this color controling gene, which is referred to as an "allele". One form of this gene is "coded" for ginger fur (written as , while the second form of this gene is "coded" for black fur.
Since females have two X chromosomes, and since the colors black and orange are assigned to the X's, a female cat can be both orange -and- black.
Normal males have only one X, so they can be either black -or- orange, and -not- both.
To summarize:
- Females have two X chromosomes, while males have one X and one Y.
- Colors in cats are assigned to the X chromosomes.
- The colors black and orange are both assigned to an X chromosome.
- Female cats, since they have two X chromosomes, can be both black and orange.
- Normal male cats, with only one X chromosome, can have either black , or orange, and not both.
But I've heard of male tortoiseshells! I KNOW they exist! Why can't I be one?!
In rare cases, a male cat (or human) will be born with an extra X chromosome, making them XXY instead of the normal XY.
This rare syndrome is called Klinefelter's Syndrome. About one in 3,000 tricolored cats are males, although only 1 in 10,000 of these males is fertile. Why, you may ask?
I may ask.
Since having more than the normal two chromosomes is a genetic mistake, this results in a cat that is different from the norm.
Due to the fact that the Klinefelter's cat (or person) has an extra female chromosome, they will produce more female hormone (called estrogen) than male hormone (called testosterone). This results in an imbalance of hormones, which almost always results in the cat (or person) winding up as sterile.
In the rare event that a Klinefelter cat is fertile, they would not be able to reproduce their calico color, because of the fact that a genetic abnormality will not be inherited.
In addition to being sterile, the higher amount of female hormone will cause physical deformities and more feminine traits.
Weak and brittle bones are common in Klinefelter's cats, and misshapen feet and limbs have been recorded. Rapid weight gain has also been witnessed in Klinefelter's cats.
In humans, other traits are common with males stricken with Klinefelter's, and would also occur in a calico in the Warriors universe, since we see them "talk" to each other:
- Delayed and decreased motor function
- Delayed speech
- Delayed maturation
- Decreased muscle development
- Increased tiredness
In the rare event that a male calico/tortoiseshell (solid or pointed) would be born in a wild cat colony like the clans in "Warriors", the problems as mentioned above would result in them dying very quickly, and more than likely they would not live past kit-hood. These are wild cats, that are forced to fight for what they have, and survive bitter conditions.
All recorded Klinefelter's cats that have survived to adulthood, live with people that take care of them. The cats in Warriors live on their own, and even a medicine cat would not be able to fix the genetic problems that these cats have.
Oh, so, the cat would die?
Most definitely yes.
..oh..
..but...
um..
*long pause*
....what about Redtail?! He was a tortoiseshell!
Authors make mistakes. "Into the Wild" was their first novel and, as you read through the first series, and as both authors have admitted, their inexperience led to numerous mistakes that include the parentage of a lot of the cats in the original books, and the coloration of the characters.
Whitestorm's eyes change color multiple times, and Tawnypelt mysteriously changes from a ginger tabby in the first series, to a tortoiseshell in the second series, for examples.
...
How about a green and purple tom? Can I make one of those?
No.
by M.Kohler.
Wait, what on earth is a tortoiseshell? Torbie? What are you talking about?
I won't bore you with the technical terms , but basically tortoiseshell is a name for a coat coloration in cats, where a shade of black or gray, and a shade of ginger (orange or red) both exist on the cat to form a unique pattern. The name "tortoiseshell" refers to cats that have little to no white markings, and whose coat is a mix of black and ginger.
Cats that have a significant amount of white in addition to the black and ginger are referred to as tortoiseshell-and-white, or as "calicos" in the United States. As the books are set in the United Kingdom, the term "calico" does not come up in the books.
Calicos and tortoiseshells may also come in "dilute" form. When dilution genes are present, the color is modified so that the black appears as gray or grayblue, and the ginger as a lighter cream or fawn.
Ahh, I see! But, what are torbies and calibys?
Torbies are cats that have tabby markings, with the addition of cream or ginger/orange markings. The dilution gene can also occur in these, causing the cat to be a lighter gray tabby with the presence of a lighter ginger or cream. Cats with torbie markings and white, are called torbie and white, or "calibys". The latter term is not used as often as the former.
It is also possible for pointed cats (i.e. "Siamese" or "Snowshoe" types) to have torbie and tortie points.
Hey, those sound pretty cool! I'm going to make a calico tom right now!
Whoa there, not so fast! In cats, calicos and tortoiseshells are almost always female; male calicos and tortoiseshells are extremely rare.
What?! I want to make my tom a calico! Why can't I?!
To answer this question, one must look at the genetics of color, and genetics in general.
As many of you probably remember from basic biology, gender in mammals is determined by two chromosomes, known as X and Y chromosomes. Females possess two X chromosomes (XX), while males possess one X and one Y (XY).
...what's a chromosome?
To explain what a chromosome is, let's summarize what the term "DNA" means. DNA, which stands for Deoxyribonucleic acid, is basically the genetic blueprint that contains instructions for development and function in living things. All living things with the exception of certain viruses, are made up of DNA.
DNA can be -very- complicated to explain, and confusing to figure out, so I'm not going to hurt your head with complex and difficult terms.
...*blank stare*...
Don't zone out on me yet! It gets easier to understand from here.
A chromosome is a long, continuous piece of DNA organized in a cell , and contains many genes.
Genes contain information that contributes to inheritance of behavioral and physical traits.
Genes that are located on either the X or the Y chromosomes are referred to as "sex-linked" genes, while genes on chromosomes other than the X and the Y are referred to as "autosomal" genes.
Below is an image of a "karyotype", which is a collection of chromosomes that make up mammals. This particular karyotype is a human male, as noted by the "XY" chromosomes seen on the very bottom right of the image.
As you can see, the Y chromosome is much smaller than the X chromosomes, and therefore contains less genes than the X chromosome does. Genes carried on the X chromosomes vary between species, and abnormal forms of these genes can result in genetic disorders.
In cats, one gene out of several that control fur color is located on the X chromosome. There are two forms of this color controling gene, which is referred to as an "allele". One form of this gene is "coded" for ginger fur (written as , while the second form of this gene is "coded" for black fur.
Since females have two X chromosomes, and since the colors black and orange are assigned to the X's, a female cat can be both orange -and- black.
Normal males have only one X, so they can be either black -or- orange, and -not- both.
To summarize:
- Females have two X chromosomes, while males have one X and one Y.
- Colors in cats are assigned to the X chromosomes.
- The colors black and orange are both assigned to an X chromosome.
- Female cats, since they have two X chromosomes, can be both black and orange.
- Normal male cats, with only one X chromosome, can have either black , or orange, and not both.
But I've heard of male tortoiseshells! I KNOW they exist! Why can't I be one?!
In rare cases, a male cat (or human) will be born with an extra X chromosome, making them XXY instead of the normal XY.
This rare syndrome is called Klinefelter's Syndrome. About one in 3,000 tricolored cats are males, although only 1 in 10,000 of these males is fertile. Why, you may ask?
I may ask.
Since having more than the normal two chromosomes is a genetic mistake, this results in a cat that is different from the norm.
Due to the fact that the Klinefelter's cat (or person) has an extra female chromosome, they will produce more female hormone (called estrogen) than male hormone (called testosterone). This results in an imbalance of hormones, which almost always results in the cat (or person) winding up as sterile.
In the rare event that a Klinefelter cat is fertile, they would not be able to reproduce their calico color, because of the fact that a genetic abnormality will not be inherited.
In addition to being sterile, the higher amount of female hormone will cause physical deformities and more feminine traits.
Weak and brittle bones are common in Klinefelter's cats, and misshapen feet and limbs have been recorded. Rapid weight gain has also been witnessed in Klinefelter's cats.
In humans, other traits are common with males stricken with Klinefelter's, and would also occur in a calico in the Warriors universe, since we see them "talk" to each other:
- Delayed and decreased motor function
- Delayed speech
- Delayed maturation
- Decreased muscle development
- Increased tiredness
In the rare event that a male calico/tortoiseshell (solid or pointed) would be born in a wild cat colony like the clans in "Warriors", the problems as mentioned above would result in them dying very quickly, and more than likely they would not live past kit-hood. These are wild cats, that are forced to fight for what they have, and survive bitter conditions.
All recorded Klinefelter's cats that have survived to adulthood, live with people that take care of them. The cats in Warriors live on their own, and even a medicine cat would not be able to fix the genetic problems that these cats have.
Oh, so, the cat would die?
Most definitely yes.
..oh..
..but...
um..
*long pause*
....what about Redtail?! He was a tortoiseshell!
Authors make mistakes. "Into the Wild" was their first novel and, as you read through the first series, and as both authors have admitted, their inexperience led to numerous mistakes that include the parentage of a lot of the cats in the original books, and the coloration of the characters.
Whitestorm's eyes change color multiple times, and Tawnypelt mysteriously changes from a ginger tabby in the first series, to a tortoiseshell in the second series, for examples.
...
How about a green and purple tom? Can I make one of those?
No.