The wild gerbil is Agouti in colour, this being a golden colour heavily ticked with black. This colour best suits the gerbil in the wild as it aids camouflage as it helps the animal to blend into its surrounding. This effectively helps to protect the gerbil from its predators. The belly of the gerbil is white as this helps the animal to thermo-regulate itself. Once in captivity and no longer needing to protect itself from predators or extremes of climate, both scientists and gerbil keepers eagerly awaited the first mutation to occur in the domestic population.

Pre-1960's

Although Mongolian gerbils had been in captivity since the 1930's, it was only in the 1960's that their popularity truly took off as a new household pet.  Soon after this date the first coat colour mutations started to appear.  None had yet appeared in laboratory populations.

Further notes on Agouti

In 1969 the first ever Gerbil Show was held by the Birmingham Mouse Club on 23 February. The event was a big success with more gerbils being shown than had been expected. All the gerbils shown were Agouti coloured.  The original standard for the Golden Agouti was published in the British magazine, Fur and Feather on April 10th of that year. In May 1969 the National Gerbil Club was formed. The announcement was made in the Fur and Feather by Bert Cooke.

Mid 1960's, The Dominant Spotting Gene (Sp)

The spotting gene first appeared in a litter of gerbils owned by the Peterson Hamstery in North Carolina. When initial numbers increased, some of the spotted gerbils were passed to Haley Farm in Virginia. The spotting gene is a dominant gene and can appear in any coat colour variety. It was imported into the UK in late 1967, sent from Canada by Frank Lane to Eric Dukes and Tony Jones. It is for this reason why this marking was commonly nicknamed Canadian Whitespot.  Over the years and also probably due to the influence of other gene mutations that seem to unfluence and interact with Dominant spotting and also the accumulation of further modifying genes that bring about the extension of white markings, have all helped to form new and different recognised patterns such as the mottled and variegated gerbils.

Late 1960's The Himalayan Gene (c^h)

The Himalayan gene which produces white gerbils with a dark tail and red eyes were reported in the UK pre 1970. The British magazine the Fur and Feather reported in 1970 that there had been white coloured gerbils, as well as spotted imports in the U.K. for a number of years.  In the U.S. it was unknown until at least the mid 1970's.

1971, The Non-Agouti Gene (a)

The first black gerbil was bred by Air force Sergeant Norman W. Olson, it was a male gerbil, it wasn't until the third litter that the parents produced 3 black females. With 3 pairs of young black gerbils and some advice from Tumblebrook Farm* Norman Olson set about breeding the pairs, the first litters were killed by the parents but eventually litters were raised and some of the offspring were given to Tumblebrook Farm for development and distribution.

The black gerbil made its debut in the UK in the late 1970's when Richard O Grady and Mina Henley working for Glasgow Zoo imported 24 of the black gerbils. After they had spent their 6 months in quarantine the gerbils were bred with the new Argente Golden (see below) eagerly hoping for a new colour.

The initial breeding of these produced 26 golden agouti gerbils as expected, it was the offspring of these gerbils that would bring the new colour. A pair of these golden agouti offspring were given to geneticist Roy Robinson, leaving the Zoo with 24.

These 24 gerbils produced 243 pups, 38 black, 43 argente golden, 146 agouti, and 16 of the new colour, Dove(now known as Lilac, the Dove coat colour as we know it today was previously known as 'Silver' by enthusiasts). However they were to be pipped at the post, as the pair that Roy Robinson had been given produced the new colour too, and a few days before Glasgow Zoo did.

In 1978/79 with the intention of keeping the Black and the new colour Lilac going, pairs were distributed free to members of the National Gerbil Society who requested them. The lines have been kept going, and the black is very common today and the Lilac although not as popular as it once was, is still available.

*Tumblebrook farm was the first commercial colony set up by Dr. Victor Schwentker.  At the time all scientific investigators obtained most, if not all of their stock from Dr Schwenker's colony.

1975, The Grey Gene (g)

The Grey Agouti gerbil was first discovered in a London petshop, it later died out but a couple of years later it appeared again and is now very common in the UK and Europe, although in the USA it is still an uncommon variety.  There were however several reports of Grey Agouti gerbils in the U.S. particularly on the Eastern Seaboard.  These may have died out prior to a further import, sent over by Brian Leiper in Scotland to the U.S. in May 1997.

The colour closely resembles the chinchilla mutations of the albino series of alleles(C locus) in mice and other domestic livestock. However through experimental crosses geneticists concluded the grey mutation in gerbils was not an allele of the albino locus and its gene symbol was designated as 'g'. The gene led to two new coat colours. On an Agouti coat it produced the Grey Agouti and when bred to a black variety it produced the Slate coat colour. In the published scientific paper;

Leiper, B.D. & Robinson, R. 1985. Gray mutant in the Mongolian gerbil. The Journal of Heredity, 76, 473.

The Slate coat colour was originally described as Dark sepia, and Slate itself was previously named 'blue' in the U.K. gerbil society (N.G.S.) because of the distinctive blue tinge the animals once had to their coats.

1977, The Pink-Eyed Dilution Gene (p)

The pink eyed gene which produced the Argente Golden was first discovered in a North London School, it was this colour which was bred with the black gerbil in Glasgow Zoo.  Fanciers soon took advantage of this new mutation, and when combined with the recently discovered grey mutation, plus the older mutations it led to many new colours.

The new colours produced were;

• Argente Golden (pp)
• Argente Cream (Cc^(h)pp)
• Lilac (aapp)
• Dove (aaCc^(h)pp)
• White-Bellied Cream (ggpp) - This colour variety was originally described as Pale cream or ivory in the previously mentioned scientific paper on the grey mutation (1985) and is probably the origin of the term "Ivory Cream" for this coat colour. 
• Ruby-Eyed White (aaggpp) - This colour variety was originally described as Off white in the above Scientific paper published about the grey mutation.
• Pink-Eyed White (c^(h)c^(h)pp)

1978, The Hairless Gene (hr) (Now Extinct)

A litter was born in the enclosure of a research lab on 6th July 1978, and some weeks later it was observed that one of the females were completely bald. Although smaller than her sisters at the age of 12 months the gerbil weighed 80g, although she looked smaller because she lacked hair. Her skin was a grey purplish colour, with a number of black spots over the rump. The ears, feet, tail & snout, were black.  These areas however also appear to be dark in normal gerbils, although this isn't obvious because they are covered by light tan coloured hair.  Although not a totally bald animal, she had smooth, warm to the touch skin, which was covered in very fine stubble. The vibrissae also had a shortened appearance. Although she was accepted by a mate, she failed to raise her first two litters. Her third litter was successfully fostered out but all the individuals were fully furred. Two other hairless gerbils, a female (6th of October 1978) and a male (19th of December 1978) were born at the colony. The female lived for only 5 weeks, and the male for just two weeks. The mutation seemed quite small and weak. This was reported in a scientific paper in 1980, by H H Swanson: The 'hairless' gerbil: a new mutant. Laboratory Animals, 14, 143-147.

photo courtesy of Heidi.H.Swanson 1980

1980 (approx), Fading Yellow Gene (e^f)

 Schimmel is the name which Germans use to describe the fading of Lippizzaner horses, and it has been used to accurately describe this gerbil coat mutation.

The mutation first occurred in the USA on or around 1980 but its origins have been poorly documented.

In Europe the German gerbil breeder and GGG (Gerbil Genetics Group) member, Vera Brückmann first observed this coat colour, in August 1994 in a pet shop in Austria. She initially gave these gerbils the descriptive name Orange Siam, because of the similarities adult Schimmels have to colourpoint coat varieties, like the Siamese. As adults they retain orange pigment only on the extremities (nose, ears, paws, and tail), and the body of the gerbils fade from it's juvenile honey colour (as a juveniles the coat colour strongly resemble that of dark eyed honeys) to an off white colour as the gerbils age. Later they discovered that this coat colour was caused by a new mutation at the Extension Locus. The dark eyed honey and schimmel coat colour mutation occurs on the same locus, but the schimmel with it's fading coat was designated the symbol e(f) (f standing for fading).

The gene arrived in the UK in March 1998 from Holland. It is still regarded as extremely rare in UK.

Mid 1980's, Extension of Yellow Gene (e)

This colour mutation first appeared in the United States; the same mutation occurred again slightly later in Europe and was first discovered in Poland. On 20 March 1993 the first gerbils with this coat colour were imported from the Poznan Zoo in Poland into Germany. In Germany the gerbil was initially called Algerian fox as previously it was thought that it was a new gerbil species that came from Algeria! Later they discovered that this "new species" was in fact a coat colour mutation of the Mongolian gerbil, and had first appeared in the United States. In October 1994, Fred Petrij (GGG member) imported the first Dark eyed Honeys, (as they are now named) into the Netherlands from Belgium.

The gene arrived in the UK in January 1997 from Holland, and has descended from these European lines. The DEH has proved to be extremely popular and can now be found in petshops in the U.K; however some of the ee coat colour varieties are still classed as uncommon in the UK.  The introduction of this gene led to an explosion of new colours.

These new colours were;

• Dark-Eyed Honey (ee)
• Red-Eyed Honey (eepp)
• Polar Fox (A*eegg)
• Nutmeg (aaee)
• Silver Nutmeg (aaeegg)
• Saffron (aaeeggpp)

Note: Due to geographical reasons, not all possible colour combinations could be produced with the appearance of the new mutant 'e' gene.  An example of this is the Silver Nutmeg coat variety which was theoretically possible in the mid 80's as all the required mutations had arisen to produce the coat colour variety by this date.  However at this time the Extension of yellow mutation 'e' was unique to North America, and the Grey gene 'g' was virtually unknown there.  In effect this meant that the very first Silver Nutmegs were not bred until the 'e' mutation appeared in Europe in the 1990's.

1994, The Chinchilla Medium Gene (c^chm)

The Burmese gerbil was discovered in a pet shop in Ireland. A former NGS member Johnathon Strutt, travelled to Ireland and purchased these gerbils and imported them into the UK. They have since been sent to the USA from Brain Leiper in Scotland in May 1997 and exported to Europe around 1996-97.

The original symbol for this mutation was c^(b) (Burmese) However for the purpose of genetic notation and in scientific literature this has been replaced by the symbol c^(chm)  after the scientific paper in the journal of heredity by Petrij F, van Veen K, Mettler M, and Brückman V. 2001, A second acromelanistic allelomorph at the albino locus of the Mongolian gerbil (Meriones unguiculatus). Journal of Heredity, 92(1), 74-78.

 The paper reports a second mutation at the C-locus that closely resembles the chinchilla medium coat variety (symbol c^chm) in the rabbit. The gene dilutes the coat, removing the yellow pigment whilst retaining colour at  the extremities. On an Agouti background it produces the Colourpoint Golden Agouti, a silver grey looking gerbil lightly ticked with cinnamon. On a self or black background the gene dilutes the coat of the black gerbil to the well-known Burmese coat variety.

The introduction of this gene when combined with the other mutations produced a flood of new colours. The main colours were; 

• Colourpoint Golden Agouti (c^chmc^chm)
• Burmese (aac^chmc^chm)
• Siamese (aac^chmc^h)
• Colourpoint Grey Agouti (Pearl) (c^chmc^chmgg)
• Black-Eyed White (c^chmc^heegg)
• Colourpoint Slate (aac^chmc^chmgg)
• Argente Fawn (Topaz) (Cc^chmpp)
• Sapphire (aaC^chmpp)

nb. Chinchilla Medium also created new ways of producing pink-eyed white gerbils

1997,The Dilution Gene (d)

 The dilute gene was discovered in Gerbils being kept at Osnabruck University. It is extremely rare in the U.K. and not currently available in the USA. Dilute Gerbils were imported into the U.K. in 2002 but were of very low fertility, and never properly distributed to breeders.  However later imports were of much better quality and continue to breed well.  The Dilute mutation behaves similar to the Maltese dilution gene in other species, but differs in the fact that it mainly dilutes black pigments, and is largely ineffective at removing yellow pigments.

To be continued...

 Article by Eddie Cope

Acknowledgements.

Gerbils All About them - Silverstein and Silverstein

Leiper, B.D. & Robinson, R. 1985. Gray mutant in the Mongolian gerbil. The Journal of Heredity, 76, 473.

Petrij F, van Veen K, Mettler M, and Brückman V. 2001, A second acromelanistic allelomorph at the albino locus of the Mongolian gerbil (Meriones unguiculatus). Journal of Heredity, 92(1), 74-78.

Swanson, H.H. 1980. The 'hairless' gerbil: a new mutant. Laboratory Animals, 14, 143-147.

Roger Edwards, Glasgow Zoo

Julian Barker, NGS Genetic information

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