The gene "cs" carried by these cats restricts the "development of color to the animal's extremities". You can read about pointing on this Siamese cat page. It is a form of albinism. Read about pointing genes on these pages about the Siamese cat.
The colorpointing changes with outside temperature and the age of the cat. An older cat will have a darker torso area due to poorer blood circulation.
Apparently, two years of age is when the pointing is the most attractive. Newborn kittens are born white. The points show gradually thereafter. The color of the points are clear after eight weeks of age. The eye color should ideally be a deep blue (as in the Siamese cat).
|Pointed British Shorthair Cat - Photo by Tscherno (Flickr)|
In the photograph above, the truth is I am not sure what type of pointing this is. It looks like tabby chocolate pointing. This is certainly tabby pointing because you can see the tabby stripes but the colors are often very subtle. This is called lynx pointing in Siamese cats.