Blue

Also known as: Standard Blue, English Blue, Powder Blue, Sky Blue, American Blue, Australian Blue, Slate Blue.

Note: The genetics information given in this article represents work in progress and may change over time. Last updated December 1st. 2002.


Origins
First reported in England in the summer of 1990, when Joan Branton, a member of the NFRS, discovered three mismarked Hooded kittens in a pet shop which were a clear bright blue, a colour never seen before by rat fanciers in the UK.

Twelve years later, the Blue rats seen at shows in the UK are an unusual, intense shade of blue (as in artist's or paint colour), with a tint quite unlike the Blue varieties of other animals which are commonly more of a slate grey shade. Darker blue rats sometimes have a violet hue, while paler shades of the colour can appear to have a slightly greenish or turquoise hue noticeable on the flanks and sides.

In the USA, the origin of the Blue rat is less certain. Its exact history has not been recorded, though the AFRMA claim it was "found in a pet shop in 1990". The puzzling similarity of story to the English discovery has not prevented the AFRMA from insisting it was an American pet shop, in the same year.

Stranger things have happened and it is not unknown for identical mutations to occur in separate parts of the world, but while the AFRMA has no record of importing Blue rats from England, the NFRS did export blue rats to the USA in the early 1990's. There are, additionally, American breeders not associated with AFRMA, who have made imports of British blues. With no definitive record of the Blue rat's first appearance in America, set against the well-documented account of its appearance in the UK and records of transatlantic export, British breeders feel sure that the Blue gene originated in England. This would go a long way to explain the genetic compatibility discussed below.


BLUE RAT FROM ENGLAND,
BRED BY SHEILA SOWTER,
CLEARLY SHOWING THE INTENSE
BLUE COLOUR AND TINT.
OWNER: CARINE VEREECKE,
RATTERY ZONIEN, BELGIUM.

Australia announced the discovery of a Blue gene in 2001, currently under development by breeders there. Descriptions and photographs strongly suggest that it is a similar gene to Blue known in the rest of the world, with the same tendency to whitish/light undercolour, and variation in shade from light to dark. In the words of one breeder, the colour is "vibrant, bright blue" with black eyes. The first Blue Agoutis in Australia were born in early 2002. As all imports of fancy mice and rats into Australia are strictly prohibited, it is assumed this is a remutation of the Blue gene known elsewhere.


Blue Standards

UK
In the UK the NFRS standard for Blue (used by all British rat clubs) calls for a dark shade of steel blue without white undercoat. Breeders have managed to achieve this through selection, and kept the white undercolour to a minimum. Non-show quality blues are frequently lighter in shade, and may have varying amounts of white undercolour.

A lighter shade of blue is occasionally seen in the UK, and was bred in the early days as Powder Blue.These are less common nowadays and are classed as an Unstandardised variety.

Europe
In the Netherlands and Belgium, where most Blue rats are descended from lines imported from the USA, blues are a much lighter shade than in the UK. Clubs in these countries classify the light blue as American Blue and the less common dark blue, imported from England, English Blue.

The shade of American blues in Europe is comparable to the UK's Powder Blue, and most have a great deal of white in the undercoat. It is in this variety that the yellow tint is most noticeable.

USA
Blue rats are standardised by all the major USA clubs:
The RMCA classifies two shades: Blue, also called Slate Blue,which is required to be as dark as possible, with dark ruby or black eyes, and Powder blue,a medium shade, lighter than slate blue, with ruby or dark ruby eyes.

The AFRMA recognises Blue, a slate blue colour, as dark as possible, and Sky Blue, a clear glittering blue in between Blue and Slate Blue. Powder Blue, though mentioned in the Sky Blue standard, does not appear to be standardised.

The RMFE also standardises three shades, all with black eyes. American Blue aka Slate Blue is a medium shade which may have a white undercolour; Powder Blue, very pale blue, and Sky Blue, which is between the two.


AMERICAN BLUE DUMBO, FROM
AMERICAN LINES, BRED IN THE UK
BY LUCIE MANN. NOTE THE YELLOW
TINT ON THE FLANKS.

Genetics of the Blue

Matings between American Blues and English Blues suggest that all shades of Blue [except Russian: see below] are produced by the same gene. Breeders in Holland, Belgium and England combining American lines with dark English blue rats have so far all produced blue offspring. Further investigation is taking place but it would not be unreasonable to conclude that the gene is the same. Nichole Royer, writing in the Summer 1999 issue of the AFRMA journal states: "Blue, English Blue, Slate Blue, American Blue and Sky Blue are genetically all the same thing."

There is some confusion over the genetic symbol used for Blue in different countries. In the USA and Europe, American Blue is given the designation g (Grey) but this has not been scientifically described.

In the UK the eminent animal geneticist Roy Robinson, author of many books including "Genetics for Cat Breeders" took a keen interest in the discovery of the Blue rat. Roy was a lifelong rat enthusiast, owner and breeder, and was responsible for introducing the Rex and Siamese genes to the rat world in the 1970's.

He took some of the first Blues to breed them himself, and considered them to be a re-appearance of the previously recorded Blue gene, symbol d (Dilution), absent from the gene pool for many years. As a result, his designation of d has been used in the UK for this colour since the early 1990's. Rediscoveries of previously recorded genes are not re-described in genetics journals, so Roy did not write a paper about the Blue rat, although he referred to it as d in his articles published in the NFRS newsletter and in at least one published scientific work.



The Russian Blue, a different gene entirely, is referred to as d (Dilution) in the USA. This colour first appeared in 1993, but was unknown in the UK until 2000, so Roy Robinson did not have the chance to see a Russian before his death in 1996. This was an enormous pity, since he would have been very interested in the variety and would surely have been able to classify it scientifically. In the absence of his guidance, and to avoid confusion with the UK's established usage of d for the English Blue, Russian is designated rb by British breeders working with the colour. Russian Blue is discussed in more detail here.


The lighter Powder Blue shade has been suggested by some to be the effect of a modifying gene, possibly the same one which lightens Mink to American Lilac. However, there may be more than one modifier which lightens the colour. A mating between a Platinum with American ancestry to a Powder Blue from English lines unexpectedly produced offspring of the dark shade favoured at shows in the UK.

Another possibility is that the light and dark shades may be different alleles of the same locus. If this theory is correct, it would be hard to say at present which might be the more dominant of the two, though it may turn out to be the darker shade. The few breeders who have been able to cross the colours so far report a variation of shade in the litters, but there are usually a few dark ones.

Certainly, if the dark shade was dominant, or incompletely dominant, it would explain why some lines of American Blues never produce dark rats, whereas many dark blue lines in the UK occasionally throw lighter blues. Nichole Royer also confirms that Powder Blues are occasionally produced in litters of dark blues in the USA. UK breeder Ann Storey, who has bred Blues from the very early days, observes that two light blues bred together never seem to produce a dark one. This could be one reason why, in certain areas and countries, the lighter blue is the more common shade.

However, presence or absence of a modifier could easily produce similar results, as could a subtle influence by other genes carried. It should be remembered too, that the first English Blues were much lighter than we know today, and would probably fall into the the Sky Blue category at American shows.


RUSSIAN BLUE REX KITTEN


ENGLISH POWDER BLUE
FROM ENGLISH LINES,
BRED AND OWNED BY
ESTELLE SANDFORD

DESCRIPTION
USAGE
GENETICS

BLUE

Dark intensely blue shade preferred for shows. Black eyes.

UK (all clubs)
USA (RMCA, AFRMA)

Recessive gene.
UK dd Scientific designation
USA gg amateur usage
Europe gg amateur usage

POWDER BLUE

Palest blue. Black eyes.

UK (Unstandardised)
USA (RMCA, AFRMA)

May be a lighter shade of blue or result of additional modifier.

SLATE BLUE

As Blue.

USA (RMFE)

As Blue.

SKY BLUE

Medium bright blue shade. Black eyes.

USA (AFRMA, RMFE)

As Blue.

ENGLISH BLUE

As Blue.

USA, HOLLAND, BELGIUM, GERMANY

As Blue.

AMERICAN BLUE

Used variously to describe lighter and medium shades. Black eyes.

USA, HOLLAND, BELGIUM
UK (unstandardised shades between Powder and standard Blue).

As Blue.

AUSTRALIAN BLUE

Light and medium shades. Black eyes.

AUSTRALIA
Recently discovered.

Believed to be same gene as Blue.

RUSSIAN BLUE

Dark greyish blue similar to blue dogs, cats & mice. Black eyes.

Used in all clubs worldwide.

Recessive gene not related to other Blue.
UK rbrb amateur usage
USA dd amateur usage
Europe dd amateur usage


Sources

Pro-Rat-A #63, May/June 1991 "Birth of the Blues" by Joan Branton
Pro-Rat-A #73, Jan/Feb 1993 "The Silver Blue" by Roy Robinson
Personal correspondence, Ann Storey, NFRS
Personal correspondence, Karen Robbins, AFRMA
Personal correspondence, Tracey York, bRatpack Rattery, Australia
AFRMA Newsletter Vol.16 No.3 "Russian Blue Rats" by Nichole Royer
AFRMA Newsletter Vol.16 No.3 "Colours & Coats" by Nichole Royer
Genetics section, http://www.rodentfancy.com (Myomorpha)
RMFE website, http://www.rodentfancy.com
AFRMA website, http://www.afrma.org
RMCA website, http://www.rmca.org

Other Contributors

Marion Benham, Chris Casteels, Lucie Mann, Estelle Sandford, Carine Vereecke.


ALL PARTS OF THIS ARTICLE INCLUDING TEXT AND IMAGES STRICT COPYRIGHT © SUE BROWN 2001/2002
NO PART OF THIS ARTICLE MAY BE COPIED OR REPRODUCED WITHOUT PRIOR PERMISSION OF THE AUTHOR.
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