Helpful hints for understanding JAX® Mice strain names

Strain type

Helpful hints for understanding inbred strain and gene nomenclature 

The parent strain designation of an inbred strain name may consist of capital letters, combinations of letters and numbers, or numbers only (e.g., DBA, C57BL, and 129). Related inbred strains, strains that have a common origin and separated before F20, are given symbols that indicate this relationship (e.g., NZB and NZW; NOD and NON). Substrains are designated by the name of the parent strain followed by a forward slash and a substrain symbol that may be a number and/or the Laboratory Registration Code of the individual or institution that maintains or generated the substrain. For example, DBA/1J, DBA/1LacJ, and DBA/2J are substrains of DBA: the numbers 1 and 2 identify the substrains, Lac is the laboratory code for Laboratory Animal Center at Carshalton, U.K., and J is the laboratory code for The Jackson Laboratory. Because genetic differences in successive substrains accumulate, so do the substrain symbols: A/HeJ is a substrain held first by Heston (He) and now maintained at The Jackson Laboratory (J).

For more detailed information on mouse strain nomenclature, consult the following:

Revised nomenclature for strain 129 mice

Although we use current 129 strain designations, we list former strain names for your convenience. For detailed information on 129 nomenclature standards, see "Revised nomenclature for Strain 129 Mice."

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Helpful hints for understanding hybrid strain nomenclature 

To name F1 hybrids, the standard strain abbreviations listed above are used. The abbreviation of the female parent is listed first and the male parent second. Thus, B6D2F1/J mice are the offspring of a C57BL/6J female mated to a DBA/2J male, and D2B6F1/J mice are offspring of the reciprocal mating. Such reciprocal F1 hybrids differ in the Y Chromosome carried by the males and the maternally-derived mitochondrial genome, and they have been exposed to different maternal environments. Thus, reciprocal F1 hybrids should not be considered genetically identical.

For more details on hybrid nomenclature, consult the "Interactive tutorial on mouse nomenclature."

Standard abbreviations used in hybrid names

Strain Abbreviation   Strain Abbreviation
129P3/J 129P   C57L/J L
129S1/SvImJ 129S   CBA/CaGnLe CBACa
A/HeJ AH3   CBA/J CBA
A/J A   C3H/HeJ C3
AKR/J AK   C3HeB/FeJ C3Fe
BALB/cByJ CBy   DBA/1J D1
BALB/cJ C   DBA/2J D2
C57BL B   NZB/B1NJ NZB
C57BL/6J B6   NZW/LacJ NZW
C57BL/6JEi B6Ei   RIIIS/J R3
C57BL/10J B10   SJL/J SJL or J
C57BR/cdJ BR   SWR/J SW

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Helpful hints for understanding JAX® GEMM® strain and gene nomenclature 

JAX® Mice are named according to the guidelines set by the International Committee on Standardized Genetic Nomenclature for Mice, and strain names are revised as necessary to conform to these guidelines.

Nomenclature for genetically engineered mice

Nomenclature for chemically-induced and targeted mutations follow the same guidelines as described for mice with spontaneous mutations (see “Nomenclature for Mice with Spontaneous Mutations”). Alleles are designated either by the chemical mutagen or by the abbreviation “tm” (targeted mutation), followed by a number and the laboratory registration code, and selection criteria superscripted to the gene symbol (e.g., Apoa1tm1Unc).

Nomenclature for mice with spontaneous mutations

Gene symbols are italicized. Symbols for recessive genes begin with a lower case letter, and symbols for dominant, semi-dominant, and co-dominant genes begin with an uppercase letter, followed by lower case letters. The gene and allele symbols for mutant genes are the same until the gene is cloned (see “Nomenclature for Cloned Mutations,” below). Different alleles of a gene may be represented by a superscript to the gene symbol. Nomenclature for a strain with a spontaneous mutation is as follows: C57BL/6J-Aw–J. When a mutation is maintained on an inbred strain background by mating homozygotes together, the gene symbol is given once. All offspring are affected mutants (phenotypically manifest the genetic mutation).

Nomenclature for cloned mutations

In 1994, the International Committee on Standardized Genetic Nomenclature for Mice voted to superscript a mutation’s symbol to the cloned gene symbol. For example, the shiverer (shi) mutation in the myelin basic protein (Mbp) gene becomes Mbpshi. If the original mutation symbol already has a superscript, the mutation and allele superscript symbols are placed on one line in the new superscript and hyphenated. For example, the myelin deficient (shimld) mutation becomes Mbpshi–mld). When a mutation occurs in a cloned candidate gene, the first letter of the gene symbol may remain uppercase, and the inheritance pattern may be conveyed in the allele symbol. For example, the recessive yellow (e) and sombre (Eso) alleles of the melanocortin 1 receptor (Mc1r) gene become Mc1re and Mc1rE–so. Mutant allele names stay the same. In this catalog, we list the previous symbol and cross-reference to the new symbol. Former gene symbols are listed under symbol common names in the strain detail. For a complete listing of nomenclature rules and guidelines, see www.informatics.jax.org/mgihome/nomen.

Nomenclature for coat color markers

Some strains (e.g., strains carrying the diabetes mutation, such as BKS.Cg-m +/+ Leprdb/J) are maintained by using coat color markers. Leprdb is maintained in repulsion with the closely linked marker misty, m, a coat color gene. The mating system we use, +/+ Leprdb x m +/+ Leprdb, produces three phenotypically distinguishable genotypes: + Leprdb/+ Leprdb mice, which are fat and black; m +/+ Leprdb mice, which are lean and black; and +/m + mice, which are lean and misty.

Nomenclature for congenic strains

Congenic strains are designated by a compound symbol consisting of the host strain (usually abbreviated), a period, the donor strain (also usually abbreviated), a hyphen, and the italicized symbol of the differential locus or loci and allele(s) (e.g., B10.129P-H12b). When the donor strain either is not an inbred or is complex, the symbol “Cg,” denoting congenic, is used. Congenic nomenclature is applied to incipient as well as to full congenics. The generation number is included in the strain detail.

The genetic background of many congenics is a mixture of C57BL/6J and a 129 substrain (designated either B6;129, B6;129P, or B6;129S; see explanation that follows on “Revised Nomenclature for Strain 129 Mice”). However, the backgrounds of some congenic strains are unknown, derived from more than two progenitor strains, or have genetic contributions from an unknown or outbred source. The background of such congenics is frequently designated as “STOCK.” Formerly, most spontaneous and induced mutations transferred by backcrossing from a mixed background (e.g., either B6;129 or STOCK) to an inbred background were not described by conventional congenic nomenclature. However, many JAX® GEMM® strain names have been revised to more clearly indicate the origin of a mutation (e.g., B6.129P2-Apoetm1Unc/J).

The Jackson Laboratory supplies a large number of histocompatibility congenic strains. In some cases, multiple lines are derived from the same donor strain and are distinguished by a number and/or letter in parentheses (e.g., B10.129P-H11b(10M)/SnJ and B10.129P-H46b H47b(21M)/Sn).

Revised nomenclature for strain 129 mice

Because 129 substrains are genetically different from each other, (Simpson et al. 1997), they must be clearly distinguished. For your convenience, this catalog contains both the updated and former 129 strain designations. For detailed information on the 129 nomenclature standards, please see “Nomenclature for Strain 129 Mice” (JAX Bulletin #1, 1999, revised June 2001). Also, see our “Interactive tutorial on mouse nomenclature.”

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Helpful Hints for Understanding Wild-derived Inbred Mice Strain Nomenclature

Wild–derived inbred mice are named according to the same standard guidelines for naming inbred strains, usually based either on where they come from geographically or who introduced them to the scientific community.

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Helpful Hints for Understanding Recombinant Inbred Strain Nomenclature

RI strains are designated, without intervening spaces, by the abbreviation of the female progenitor strain, an upper case letter “X,” the abbreviation of the male progenitor strain, an Arabic number indicating the RI line, a forward slash, the ILAR-assigned Registration Code of the scientist who developed the strain, and the Registration Code of the laboratory that maintains and distributes the strain. For example, AKXD1/TyJ is the first (1) RI line derived from a cross between an AKR/J (AK) female and a DBA/2J (D) male, was developed by Benjamin Taylor (Ty), and is now maintained and distributed by The Jackson Laboratory (J). All members of an RI set are serially numbered, regardless of how many laboratories produced them. Serial numbers may be obtained from Mouse Genome Informatics (nomen@informatics.jax.org).

Exceptions to this nomenclature format are made in three cases: 1) when an RI strain progenitor cannot be differentiated from another RI progenitor by an abbreviation of less than three letters; 2) when the paternal progenitor strain abbreviation ends in an Arabic numeral, in which case a hyphen is inserted before the individual strain number; 3) when members of an RI strain set have been identified for many years by capital letters rather than numbers.

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Recombinant Congenic Strain Nomenclature

An RC strain is designated, without intervening spaces, by the abbreviation for the recipient, a lower case “c,” the abbreviation for the donor, an Arabic numeral designating the strain’s number within the set, a forward slash, the Registration Code of the scientist who produced the strain, the Registration Code of subsequent holders (if a substrain) and the Registration Code for the laboratory that maintains and distributes the strain. For example, NONcNZO5/LtJ is the fifth member of an RC strain set derived from a cross between NON/ShiLtJ and NZO/HlLtJ, developed by Edward Leiter (Lt), and maintained and distributed by The Jackson Laboratory (J).

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Consomic (Chromosome Substitution) Nomenclature

Consomics are designated, without intervening spaces, by the full strain name of the host strain, a hyphen, the abbreviation for “chromosome” and an Arabic number denoting the transferred donor chromosome, the superscripted donor strain symbol, a forward slash, the ILAR-assigned Registration Code of the scientist who produced the strain, and the Registration Code for the laboratory that maintains and distributes the strain. For example, C57BL/6J-Chr1A/NaJ carries Chr 1 from strain A/J (A) on a C57BL/6J background, was constructed in the laboratory of Joseph Nadeau (Na), and is maintained at The Jackson Laboratory (J).

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Helpful Hints for Understanding Nomenclature for Mice with Chromosomal Abberations

Chromosome aberrations are designated by a letter abbreviation identifying the type of aberration (see following chart), the number(s) of the chromosome(s) involved in parentheses, and a series symbol. The series symbol consists of the ILAR-assigned Laboratory Registration Code for either the person or laboratory that discovered or produced the aberration, preceded by a series number for either that investigator or laboratory. Symbols may be abbreviated by removing the parenthetical chromosome information.

In

Inversion (e.g., In(5)30Rk  in STOCK In(5)30Rk/J, Stock Number 000852)

Is

Insertion (e.g., Is(7;1) 40H (part of Chr 7 into Chr 1) in C3H/HeJ-pJ Is(7;1)40H/J, Stock Number 002460)

Rb

Robertsonian chromosomes (translocations) (e.g., Rb(6.16)24Lub (swap of pieces of 6 and 16 – 6 attaches to 16; 16 attaches to 6)) in STOCK Rb(6.16)24Lub, Stock Number 000885)

T Translocation

Tp

Transposition (e.g., Tp(Y)1Ct in B6-Aw-J-EdaTa-6J.Cg-Sxrb Hya-/J, Stock Number 001730) (segment of Y short arm transposed to distal long arm)

Ts

Trisomy (e.g., Ts(1716)65Dn in B6EiC3Sn a/A-Ts(1716)65Dn, Stock Number 001924) (Actually, this is only a partial trisomy because whereas a trisomy is three copies, this only has a piece of Chr 16 attached to Chr 17.)

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