The Tortie Point Siamese Cat
Just what is a Tortie Point Siamese cat?
A Tortie Point or 'tortoiseshell' Siamese is a cat that, instead of having solid points, has points that look like a tortoise shell.
Let's take Seal, Blue or Caramel Points as examples.
In the Tortie Point version of these, their face, nose, ears, legs, feet and tail are found in often unusual and beautiful mottled or spotted combinations, of Seal/Red, Blue/Cream and Caramel/Apricot.
So how do you get a Tortie Point?
The Tortie Point Siamese has come about through some complicated breeding.
Bear with me, this might take some explaining, and I'm certainly not a geneticist, so, in very simple terms ...
Tortie genetics for beginners
Purebred Seal, Blue, Chocolate and Lilac, as well as Cinnamon, Caramel and Fawn Point Siamese don't carry the orange or 'O' gene.
The gene that codes for orange effectively turns black coloring into ginger, in cats. Red, apricot and cream are all shades of ginger caused by the presence of the orange gene.
When a Siamese in one of the solid colors (Seal, Blue, Chocolate, etc., which don't have the orange gene) is crossed with a cat that does have the orange gene, one of several things may happen. But first ...
Blue Tortie Point Siamese
photo: © Martin Bahmann | Creative Commons
Some slightly more advanced genetics
If you know anything about genes, you'll know that they're carried on chromosomes. Females have paired XX chromosomes, males have XY chromosomes.
The orange gene is only carried on the X chromosome.
Because a male cat only has one X chromosome, if he inherits an orange gene it will change all his black or otherwise dark coloring (his Points, in a Siamese cat's case) to a shade of ginger. So a male cat only needs to inherit one orange gene in order to give him red, apricot or cream Points.
A female cat, on the other hand, having two X chromosomes, needs to inherit orange genes on both chromosomes in order to give her totally red or apricot or cream Points.
Seal Tortie Point Siamese cat
photo: © Kamée | Creative Commons
The cause of the tortoiseshell effect
If a female cat inherits the orange gene on only one of her chromosomes, it will only change half her pigment to one of the red shades. The other half will remain as it would have been without the orange gene.
So the Siamese tortoiseshell cat comes about because half of points turn to red; in the case of Seal, Chocolate or Cinnamon Points, to red; Blue and Fawn Points to cream, and Caramel Points to apricot.
This also explains why tortoiseshell cats are almost always female – a tortoiseshell male cat would be very, very rare – and a genetic abnormality.
The different forms of Tortie Point
There are seven different varieties of Tortie Point Siamese cat. Their colors are described by the Governing Council of the Cat Fancy as follows:
Seal Tortie
Points: Seal brown with shades of red
Body: Cream. In kittens the body colour may be muddy fawn
Blue Tortie
Points: Light blue with shades of cool toned cream
Body: Glacial white
Chocolate Tortie
Points: Milk chocolate with shades of red
Body: Ivory
Lilac Tortie
Points: Pinkish grey with shades of cool toned cream
Body: Off-white (magnolia)
Cinnamon Tortie
Points: Warm cinnamon brown with shades of red
Body: Ivory
Caramel Tortie
Points: Brownish grey with shades of apricot
Body: Off-white (magnolia)
Fawn Tortie
Points: Warm pale rosy mushroom with shades of cream
Body: Off-white (magnolia)
So now you know!
And the next time you see a Siamese Tortie Point cat, you'll be able to impress your friends with your new-found knowledge, both of cats, and genetics!
Seal Tortie
photo: © Kamée | Creative Commons
Read on! Related red color point pages:
***************
Or go to:
Top of Tortie Point Siamese Cat
Siamese Cat Colors - An Overview
Life with Siamese Cats Home Page
Enjoy this page? Don't miss out - sign up for our
free newsletter, Meezer Musings
Goings-on in the Siamese world - news, stories, photos,
cat shows and our Meezer of the Month!
You can find us
on Facebook
and Twitter
