Condensed Strain Nomenclature Guidelines

The complete guidelines for strain nomenclature can be found at /nomen/rules-for-nomen.shtml.

Strain Type	Characteristics	Nomenclature
Inbred Strain	Mated brother x sister or youngest parent x offspring for 20+ consecutive generations.	Symbol designated by capital letter or letters (four letters or fewer) in Roman type; e.g. BN, SHR
Related Inbred Strain	Strain with common origin but separated before F20.	Symbol should indicate the relationship. Symbols should be together in the alphabetical list; e.g. SS, SR
Substrain	Genetically diverged inbred strains due to: 1.separation after 20 but before 40 generations of inbreeding 2.observation of genetic differences (residual heterozygosity or mutation) between branches 3. separation of branches for 20+ generations.	Name of the parent strain, slash, ILAR code (Institute for Laboratory Animal Research Up to three ILAR codes can be added in a symbol; e.g. WKY/N, BN/NHsdMcwi
Recombinant Inbred Strain	Formed by crossing 2 inbred strains followed by 20+ generations of brother x sister mating.	Abbreviation of both parental strain names separated with capital X with no space. Different RI strains in a series are distinguished by numbers following the symbol; e.g. BXH1, BXH2
Coisogenic Strain	Inbred strains that differ at only a single locus through mutation occurring in that strain.	Strain symbol or substrain symbol followed by a hyphen and the gene symbol of the differential allele in italics followed by the ILAR code of the lab; e.g. BN-RT1^n/Rj
Congenic Strain	Produced by repeated backcrosses to inbred (background) strain with selection for a particular marker from the donor strain. Minimum 10-backcross generation to the background strain should be made.	Abbreviated symbol of the recipient strain, period, abbreviated symbol of the donor strain, hyphen, the differential allele (in italics), slash, ILAR code of the lab. If a chromosomal segment has been transferred list the most proximal and the most distal markers in parenthesis separated by a hyphen (in italics); e.g. LEW.BN-tl, SHR.BN-(D13Arb5-Ren)/Ipcv
Consomic Strain/Chromosome Substitution Strain	Produced by repeated backcrossing of a whole chromosome onto an inbred strain. Minimum of 10 backcross generations is required.	Abbreviated host strain, hyphen, chromosome number, strain of origin in superscript, followed by a slash, ILAR code of the lab; e.g. SS-2^BN/Mcwi
Segregating Inbred Strains	Inbred strains in which a particular allele or mutation is maintained in heterozygous state.	Named as inbred strains with the segregated locus is a part of the standard genotype
Conplastic Strain	Nuclear genome from one strain has been crossed onto the cytoplasm of another, mitochondrial donor is always the female parent.	Abbreviated strain with the nuclear genome, hyphen, mt (mitochondrial) in superscript, strain of the cytoplasmic genome
Transgenic Strain	Any DNA that is stably introduced into the germline of a rat.	Symbol of the strain followed by hyphen then Tg denoting transgenic strain, in parentheses, the official gene symbol of the inserted DNA followed by then laboratory’s line or founder designation or a serial number slash the ILAR code of the originating lab; e.g., SD-Tg(GFP)Bal/2Rrrc.
Targeted mutations	Mutations/deletions/disruptions of gene targeted by homologous recombination	Symbol of the strain followed by hyphen then symbol of the targeted gene then superscript consisting of three parts tm to denote targeted mutation, serial number of the lab of origin and the ILAR code of the lab; e.g., (Mouse strain) 129-Trp53^tm1Holl