Sunday, 6 January 2008

>>Hairless dog

Hairless dog

A hairless dog is a dog with a genetic disposition for hairlessness. There are two known types of genetic hairlessness, a dominant and a recessive type.

Dominant genes

Dogs with dominant genes for hairlessness can pass their attributes to their offspring in natural conditions, that is, not under the control of humans. Therefore, it is possible that, in some parts of the world, groups of hairless dogs came into existence without human intervention. Later in history, people developed these groups into a recognized breed.

African Hairless Dog at the Walter Rothschild Zoological Museum, Tring, England
African Hairless Dog at the Walter Rothschild Zoological Museum, Tring, England

Recognized breeds at this time are the Chinese Crested Dog, the Mexican Hairless Dog, and the Peruvian Hairless Dog. Other breeds there are said to exist are the Hairless Khala, African Hairless Dog (also known as the Abyssinian Sand Terrier, Egyptian Hairless Dog and Elephant Dog, the last being a reference to its grey skin) and the Thai Hairless Dog.

This type of genetic structure is said to be homozygous lethal for the dominant gene. This means that dogs with two dominant genes cannot live. Therefore, all dominant-hairless dogs have a heterozygous gene structure. There is also a homozygous recessive type, which is a coated variety.

On average, every litter of hairless puppies should include some coated ones. Statistically, for every 2 hairless puppies, there should on average be one coated.

However, some breeders claim varying averages from 1:0 to 2:1; that is, some breeders claim to have no coated offspring in any of their litters, while others claim to have an average ratio of 8:1 or 4:1 or 2:1. Averages that show more coated than hairless are not known.

The Chinese Crested coated variety is called "Powder Puff", and is a recognized type. For the other breeds coated varieties are called "coated" and are not recognized as valid varieties for show dogs.

Recessive genes

Dogs with a recessive gene for hairlessness are not known in natural conditions. The only known such breed, the American Hairless Terrier, is created by mankind.

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