Genetics & Abbreviations

Welcome to the genetics reference page of Guldsten Rattery.

This page explains the genotype notation used throughout our breeding program and provides an overview of the genetic abbreviations found on each breeding profile.

Whenever possible, all breeding animals are documented with their known genotype. Our goal is to promote transparency, preserve valuable genetic information, and support responsible breeding practices.

The notation follows established rat genetics wherever possible. For traits without an officially recognized international gene symbol, internal abbreviations are used for consistency and clarity.

Our Breeding Database

At Guldsten Fancy Rats, every rat is carefully documented, regardless of whether it was born here or imported from another breeder.

To keep accurate and consistent records, I developed my own breeding database using Google Sheets, tailored specifically to my breeding program. Every rat has its own individual profile containing pedigree information, genetics, health records, breeding history, offspring, and other important observations throughout its life.

For imported rats, I also maintain an extensive ancestry database. This allows me to continuously add new information about ancestors, health, genetics, longevity, temperament, and other valuable findings as they become available.

This continuously growing database enables me to make well-informed, long-term breeding decisions, preserve valuable bloodlines, trace pedigrees across generations, and maintain complete transparency within my breeding program.

Reading the Genotype

Each gene consists of two alleles, one inherited from each parent.

Examples

Genotype: Meaning:

A/a Agouti carrying Non-Agouti

a/a Non-Agouti

D/d Full Colour Intensity carrying Dilute

d/d Dilute (English Blue)

RB/rb No Russian blue, Russian Blue carrier!

rb/rb Russian Blue

Sm/sm Silvermane

Unknown Alleles

An asterisk (*) indicates that the second allele is unknown or has not been genetically confirmed.

Examples

• B/*

• RB/*

• HE/*

• C/c*

Genotype Abbreviations

Genotypes are written using standard genetic notation, where uppercase letters represent dominant alleles and lowercase letters represent recessive alleles.

The following abbreviations are used throughout this website.

Symbol Description

• A Agouti

• a Non-Agouti

• B Black locus

• b Brown locus

• C Full Colour

• ce Burmese

• ch Siamese / Himalayan

• c* Confirmed Colourpoint allele (ce or ch), exact allele unknown

• D Full Colour Intensity

• d Dilute (Blue / English Blue)

• RB No Russian Blue

• rb Russian Blue

• P No Pink Eye Dilution

• p Pink Eye Dilution

• H Self allele (dominant)

• h Hooded allele. Together with other hooded alleles and modifiers, it determines markings such as Irish, Berkshire, Hooded, Variegated, Bareback, Capped, etc. 

  • • • • • Note: The hooded locus includes multiple alleles (e.g. H, h, h(e), h(i)), which, together with modifier
            genes, determine the final white marking pattern.

• HS No Headspot

• hs Headspot

• Sm Silvermane (internal abbreviation)

• sm no Silvermane

• Ro No Roan

• ro Roan

• DM Top Ears (Standard Ears)

• dm Dumbo Ears

• Hr No Hairless

• he Hairless

• re no Rex, Normal Coat

• RE Rex 

• Hl No Harley (No Longhair), Normal Coat

• hl Harley, Longhair

• VE Velveteen

• ve no Velveteen, Normal Hair

• DW Dwarf

• dw Normal Size

Carrier Information

Only genetically confirmed carriers are listed under Carrier.

Possible or statistically suspected carrier status is not displayed unless supported by pedigree analysis, test breeding, or confirmed genetic evidence.

This approach ensures that all published carrier information remains as accurate and reliable as possible.

Genotype vs. Variety

The Variety describes the rat’s visible appearance (phenotype).

The Genotype describes the known genetic makeup, including recessive genes that may not be visible.

Two rats may therefore appear identical while carrying very different genetic traits.

References

The genetic information published on this website is based on current knowledge from established rat genetics, pedigree analysis, and responsible breeding practices.

Primary references include:

• American Fancy Rat & Mouse Association (AFRMA)

• Rattery Castor (Netherlands)

• Farbrattengenetik.de

• Published breeder records and pedigree analysis

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This page is continuously updated as new scientific knowledge and breeding experience become available.