Introduction
In today's research environment the need to clearly understand the history and origin of mouse strains is critical to structuring successful research programs that minimize variability. Standardized mouse nomenclature aids in the communication of a strain's name, origin and history.
JAX® Mice bred and distributed from The Jackson Laboratory and Charles River Laboratories in Europe and Japan are bred using established practices that reduce the likelihood of genetic drift and therefore help researchers:
- Control experimental variability
- Increase reproducibility
- Help ensure the long-term viability of their data
Investigators are advised to research the breeding and development history of the strains they depend on for their experiments. We also advise that they be informed of any characteristic mutations present in the genetic background of the strains they use that may impact experimental design or data interpretation.
Mouse
Gene & Strain Nomenclature
Mouse
Gene & Strain Nomenclature
Inbred Mice
- Inbred mouse strains are bred within a closed colony (by sibling matings) to maintain certain defining characteristics. Animals that result from at least 20 consecutive generations of brother x sister matings are considered inbred.
- Inbred strain names begin with the parent strain designation (indicated by a brief, unique symbol made up of upper case roman letters, or a combination of letters and numbers), followed by a forward slash (/) and substrain designation.
- Several hallmark research and disease studies as well as major collaborative initiatives such as The Mouse Genome Project, The Mouse SNP Database, and The Mouse Phenome Project have included JAX® Mice as critically important components.
C57BL/6J
to The Jackson Laboratory at F24 in 1948
C57BL
parent strain designation
/
(forward slash) separates the parent strain from the substrain
6
line number
J
Laboratory code for The Jackson Laboratory
6J
substrain designation
Mouse
Gene & Strain Nomenclature
F1 Hybrids
- F1 hybrids are the progeny of an outcross between two different inbred strains.
- F1 hybrids are designated using upper case abbreviations of the parent strains, with the maternal strain abbreviation listed first, followed by F1 and the laboratory code.
C57BL/6J
female progenitor
129S1/SvlmJ
male progenitor
F1
first filial generation
J
laboratory code for The Jackson Laboratory
Mouse
Gene & Strain Nomenclature
F2 Hybrids
- F2 hybrids are the progeny produced from intercrossing two F1 hybrids.
- F2 hybrids are designated first with the abbreviation of the female progenitor from the F1 initial cross.
- F2 hybrids are designated first with the abbreviation of the female progenitor from the F1 initial cross, then the abbreviation of the male progenitor from the initial cross.
- F2 hybrids are designated first with the abbreviation of the female progenitor from the F1 initial cross, then the abbreviation of the male progenitor from the initial cross, followed by F2.
- F2 hybrids are designated first with the abbreviation of the female progenitor from the F1 initial cross, then the abbreviation of the male progenitor from the initial cross, followed by F2 and the laboratory code.
C57BL/6J
female progenitor
129S1/SvlmJ
male progenitor
F2
second filial generation
J
laboratory code for The Jackson Laboratory
Mouse
Gene & Strain Nomenclature
Congenic Strains
- An incipient congenic strain is formed by backcrossing a locus of interest onto an inbred strain for five to nine generations (between N5 and N9).
- A congenic strain is formed by backcrossing a locus of interest onto an inbred mouse strain for 10 or more generations (greater or equal to N10).
- Congenic and incipient congenic strains are designated by a compound symbol consisting of the recipient and donor strain abbreviation separated by a period (.)
- Congenic and incipient congenic strains are designated by a compound symbol consisting of the recipient and donor strain abbreviation separated by a period (.), followed by a hyphen,
- Congenic and incipient congenic strains are designated by a compound symbol consisting of the recipient and donor strain abbreviation separated by a period (.), followed by a hyphen, and the symbol (in italics) of the differential allele(s) introgressed from the donor strain.
- Congenic and incipient congenic strains are designated by a compound symbol consisting of the recipient and donor strain abbreviation separated by a period (.), followed by a hyphen, and the symbol (in italics) of the differential allele(s) introgressed from the donor strain.
- Congenic and incipient congenic strains are designated by a compound symbol consisting of the recipient and donor strain abbreviation separated by a period (.), followed by a hyphen, and the symbol (in italics) of the differential allele(s) introgressed from the donor strain.
Statistical Percentage of the Recipient Genome with Increasing Generations of Backcrossing
Donor Strain
B6;129P2-Apoa1tm1Unc
Donor Strain
129P2 via E14TG2a ES cell line
;
(semicolon) indicates a mixture of C57BL/6 and 129P2 (from ES cell line). This colony had been backcrossed to C57BL/6 for less than 5 generations.
.
(period) indicates this colony had been backcrossed to C57BL/6 for at least 5 generations.
J
laboratory code for The Jackson Laboratory
Mouse
Gene & Strain Nomenclature
Spontaneous, Chemical and Radiation-Induced Mutations
- A spontaneous mutation occurs in a gene due to a random genetic event; random mutations can also be induced through exposure to chemicals or radiation.
- Spontaneous mutations are assigned descriptive symbols (e.g., lpr = lymphoprofileration), until the gene underlying the mutation has been identified.
- Spontaneous mutations are assigned descriptive symbols (e.g., lpr = lymphoprofileration), until the gene underlying the mutation has been identified.
- Spontaneous mutations are assigned descriptive symbols (e.g., lpr = lymphoprofileration), until the gene underlying the mutation has been identified.
- Thereafter, a function-based gene symbol is assigned and the former descriptive gene symbol is superscripted to the new gene symbol to indicate it is an allele of that locus (e.g., lpr became Faslpr).
- Spontaneous mutation strain names begin with the genetic background, followed by a hyphen (-)
- Spontaneous mutation strain names begin with the genetic background, followed by a hyphen (-), then the mutation symbol.
- A lab code, separated by a forward slash (/), can be added to the end of the strain name to identify the substrain.
lpr
Faslpr
MRL/MpJ-Faslpr/J
A -> G Spontaneous Mutation resulted in lymphoproliferation, indicated as lpr (recessive)
MRL/MpJ
genetic background
-
(hyphen) separates the genetic background from the locus of interest
Fas
gene symbol, in italics (Fas gene symbol for FAS - TNF receptor superfamily member)
lpr
allele (superscripted) for lymphoproliferation (named based on prominent characteristic)
J
laboratory code for The Jackson Laboratory
Mouse
Gene & Strain Nomenclature
Targeted Mutation (Knockout/Knockin)
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Gene targeting by homologous recombination in embryonic stem (ES) cells results in mutations that impair, prevent, or alter gene expression.
- Targeted mutation strain names consist of the genetic background and the mutation symbol separated by a hyphen.
- The symbols for both gene and allele are written in italics using the gene symbol of the targeted gene, with a superscript consisting of three parts:
- The symbols for both gene and allele are written in italics using the gene symbol of the targeted gene, with a superscript consisting of three parts: the symbol tm to denote a targeted mutation,
- The symbols for both gene and allele are written in italics using the gene symbol of the targeted gene, with a superscript consisting of three parts: the symbol tm to denote a targeted mutation, a unique number,
- The symbols for both gene and allele are written in italics using the gene symbol of the targeted gene, with a superscript consisting of three parts: the symbol tm to denote a targeted mutation, a unique number, and the laboratory code.
- Another laboratory code, separated by a forward slash (/), can be added to the end of the strain name to identify the substrain.
implant pseudopregnant mother with blastocysts containing apolipoprotein A1 (Apoa1) targeted mutation made in 129P2 derived ES cells
chimeric progeny
test for germline transmission, then backcross to recipient strain for less than 5 generations
backcross donor strain to recipient strain for at least 5 generations
B6.129P2-Apoa1tm1Unc/J
;
(semicolon) indicates colony had been backcrossed to C57BL/6 for less than 5 generations
.
(period) indicates colony had been backcrossed to C57BL/6 for at least 5 generations
129P2
donor background abbreviation (129P2 via E14TG2a ES cell line)
-
separates the genetic background from the locus of interest
Apoa1
targeted gene, apolipoprotein A1
tm
indicates a targeted mutation
Unc
laboratory code for the University of North Carolina
J
laboratory code for The Jackson Laboratory
Mouse
Gene & Strain Nomenclature
Transgenic Strains
- A transgenic strain contains an engineered fragment of DNA.
- This DNA (human, mouse, etc.) is incorporated into the mouse genome by random insertion into the embryo usually by microinjection into the male pronucleus.
- Strain names containing transgenes begin with the genetic background
- Strain names containing transgenes begin with the genetic background followed by a hyphen (-), the transgene designation (Tg),
- Strain names containing transgenes begin with the genetic background followed by a hyphen (-), the transgene designation (Tg), the insert designation in parentheses,
- Strain names containing transgenes begin with the genetic background followed by a hyphen (-), the transgene designation (Tg), the insert designation in parentheses, the serial number,
- Strain names containing transgenes begin with the genetic background followed by a hyphen (-), the transgene designation (Tg), the insert designation in parentheses, the serial number, and finally the lab code.
C57BL/6-Tg(CAG-EGFP)1Osb/J
C57BL/6Jinject transgene to generate multiple founder lines
C57BL/6
genetic background
CAG-EGFP
insert designation: Human cytomegalovirus immediate early enhancer and chicken beta-actin/rabbit beta-globing hybrid promoter / enhanced green fluorescent protein derived from the jellyfish Aequorea victoria
Osb
laboratory code for Dr. Masaru Okabe, Osaka University
J
laboratory code for The Jackson Laboratory