Are bicolor cats rare, friendly, hypoallergenic?

Tuxedo cats are bicolor cats. This is my darling deceased female. Image: MikeB

Bicolor cats are cats with a coat of two (as in 'bi') colors: white and another colour such as black or ginger. And the 'other colour' can have tabby markings. 

They can be moggies (random-bred cats) or purebred, pedigree cats. It does not matter which. They are common and therefore not rare. Neither are they hypoallergenic but they are friendly if they've been socialised properly and treated well.

No domestic cat is hypoallergenic as the Fel D1 allergen is produced by all domestic cats. Purina LiveClear works pretty well to make a cat acceptable to a person allergic to cats.

'Hypoallergenic' means not producing an allergic reaction in people. About 10% of people are allergic to cats.

The white fur in bicolor cats is caused by the presence of the piebald aka white spotting gene, which affects the migration of pigment producing cells (melanocytes) in the skin during the development of the embryo. 

Where there are no melanocytes there is no melanin in the hair strands. White fur does not contain pigment namely melanin.

It is white because the light from sun or room light passes through it. White light is a mixture of all the colours of the rainbow.

Melanin is a brown/black. If it is diluted, black becomes blue grey and red becomes cream and so on.

The experts rate bicolor cats from 1 to 10 depending on the amount of white fur. Level 1 is black and no white fur while level 10 is all-white. The cat in the picture is about level 4.

If you have a question, ask in a comment and I'll be pleased to respond. I always check comments as I get so few! :)

Level 9 bicolor Cornish Rex. Image in the public domain.

Dickkopf 4 (Dkk4) gene vital to the process of creating cat fur patterns

The research results report is impenetrable for the average layperson. I would politely ask the scientists to provide a second write-up of their research in straightforward English so the general public can understand it. Thanks in advance. This is important research which is central to understanding one of the most important features of domestic cats: the appearance of their coat. It is the most important aspect of the cat's appearance. Please tell us how it works in plain English. I am sure that even the science journalists struggle with the scientists' write-up.

Dickkopf 4 (Dkk4) gene vital to the process of creating cat fur patterns. Image: The researchers.

One of the scientists involved, Dr. Gregory S. Barsh. said to The New York Times:

"We think this is really the first glimpse into what the molecules (involved in pattern development) might be".

They carried out the research at the HudsonAlpha Institute for Biotechnology in Huntsville, Alabama, USA.

The research identified a gene they have called Dickkopf (Dkk4) as the centre of the process of cat coat pattern development.

"The secreted Wnt inhibitor encoded by Dickkopf 4 plays a central role in this process, and is mutated in cats with the Ticked pattern type".

They analysed skin samples from non-viable cat embryos for the study. Note: they made that clear I guess to avoid criticism of animal testing. Good. It shows a sensitivity towards the immorality of animal testing.

They used the embryos to explore the genetics behind a wide range of cat coat patterns. The original pattern for the domestic cat is the mackerel tabby (my comment) as it comes from the North African wildcat, the domestic cat's wild ancestor. All tabby cats have the famous M mark on their forehead, sometimes almost invisible.

Associated: Why are tabby cats so common?

At birth all cats have developed their coat type that they'll have for their lives.

Image: the researchers.

The gene Dkk4, as it changes in the embryo, dictates the pattern. They found that this 'signalling molecule' is behind all the coat appearance of a range of animals including cheetahs, tigers, leopards and the domestic cat.

Associated page: Cat coats tabby.

Differences in the expression of the molecule during the development of the embryo produces the variety of coat patterns during later hair growth.