New 129 Nomenclature - revised
JAX® Bulletin Number 1
June 1999; Revised June 2001
A large degree of genetic diversity among 129 substrains was recently identified by scientists at The Jackson Laboratory (Simpson et al., Nat Genetics 16:19-27, 1997), and subsequently by investigators at Case Western Reserve University (Threadgill et al., Mamm Genome 8:390-393, 1997). Because of the importance of 129 mice in creating "knockout" and other targeted mutant mice, the International Committee on Standardized Genetic Nomenclature for Mice introduced a new nomenclature to distinguish different 129 parental lines and related 129 strains.
The overall result is a change in 129 nomenclature that specifies groups of strains related by their common parental lineage. The major parental lineages include:
- 129 strains derived from the original parent strain (designated by the letter P)
- 129 strains derived from a congenic strain made by outcrossing to introduce the steel mutation (designated by the letter S)
- 129 strains derived from the 129 congenic that originally carried the teratoma mutation (designated by the letter T).
The numbers following the letters (e.g., P3) distinguish the different 129 parent strains within each lineage.
These nomenclature changes affect the strain names for inbred 129 mice and all mice carrying transgenes, or spontaneous or targeted mutations on a 129 background. The Jackson Laboratory has updated the 129 strain names for relevant JAX® Mice in the 1999 Price List and Product Guide, and subsequent JAX® Mice catalogs, which also list former strain names for your convenience.
Many targeted mutations (e.g., "knockouts") are maintained on a mixture of C57BL/6 and a particular 129 strain. This mixed genetic background was previously designated simply B6,129 and subsequently B6;129. Strain names have been revised, e.g., B6;129P or B6;129S, distinguishing between 129 strains of the parental (P) or steel (S) lineages.
The exact origin and breeding history of some spontaneous and targeted mutations maintained on either a 129 background or mixed B6;129 is unknown. Therefore, substrain information has been eliminated from some strain names, and they are designated simply 129 or B6;129.
A copy of the article by Festing, et al. (Mammalian Genome, 10:836, 1999) further describing the rationale behind the nomencla-ture changes and the revised nomenclature for strain 129 is found below.
If you have any questions regarding this change, contact Jackson Laboratory Technical Support at tel: 800 422-MICE(6423) or 207 288-6423; fax: 207 288-6150.
Revised Nomenclature for Strain 129 Mice
Michael FW Festing (1), Elizabeth M Simpson (2), Muriel T Davisson (2), Larry E Mobraaten(2).
- MRC Toxicology Unit, University of Leicester, PO Box 138, Leicester LE1 9HN, UK.
- The Jackson Laboratory, Bar Harbor, Maine, USA.
Need for revised nomenclature
Two recent papers (Simpson et al., 1997; Threadgill et al., 1997) have shown that there is substantial genetic variation among substrains of this important inbred strain. Some of this has apparently arisen as a result of genetic contamination, and the rest appears to be due to residual heterozygosity and/or "contaminant" alleles introduced during various backcrossing programs such as in the production of congenic strains carrying steel and susceptibility to teratomas.
Correct identification and designation of substrains is essential if the genotype of the mouse strain is to be matched accurately with an appropriate embryonic stem cell line in the development of "knockout" strains. Unfortunately, current nomenclature makes this difficult. Thus substrains 129/SvJ and 129/SvJae are very different, but this is not immediately obvious even to someone with a good understanding of nomenclature rules. Moreover, some substrains can only be accurately identified using nomenclature involving quite complex gene symbols. Thus, in view of the widespread use of these strains by people with little understanding of genetic nomenclature, it seems sensible to introduce new, simpler, nomenclature which will minimise future misunderstandings particularly as investigators have sometimes referred to different substrains as simply "129", adding further confusion.
The new nomenclature
The following new nomenclature has been approved by the Committee on Standardized Genetic Nomenclature for Mice. The aim is to provide short symbols that distinguish different substrains when they are abbreviated from the frequently long and complicated substrain symbols, either in common usage or in manuscripts. The new nomenclature is based on the substrains identified and defined in terms of microsatellite markers by Simpson et al., (1997). A letter and a number have been introduced in front of the slash that will unequivocally identify each of the substrains. The letter is either P, S, T or X indicating whether it is a "Parental", "Steel", "Ter" (i.e. susceptible to teratomas) or a genetically-contaminated "X" substrain [See JAX® Notes No. 481, Feb. 2001], respectively. A number will be used to differentiate between substrains within each grouping, working from left to right in Fig. 2 of Simpson et al. , (1997). All existing substrain symbols and gene symbols will be retained. The only change is the introduction of a letter and a number in front of the slash. A genuine congenic strain such as 129/ReJ-Lama2 dy will take the strain designation of its partner, i.e. it will be designated 129P1/ReJ-Lama2 dy. This nomenclature change is equivalent to that used to distinguish between RIII and RIIIS, where the latter differs substantially from the former. Table 1 shows the approved new nomenclature for each substrain. Note that 129/Sv (000094), which exists as frozen embryos and has been discovered to be heterozygous at many loci, has not been included on this list as it is clearly not an inbred strain. 129/SvEmsJ (002065) and 129/SvEms (002064) are presumed to be genetically identical. [129S1/SvImJ (002448) was derived from 000090, 129S1/Sv-+p + Tyr-c Kitl Sl-J/+ (formerly Mgf Sl-J/+; see JAX® Notes No. 481, Feb. 2001) in 1995 by selectively breeding out the steel Jackson mutation. Therefore, except for the region surrounding Kitl on Chr 10, these two strains are genetically identical. Designated 129S3/SvImJ in 1999 (Festing et al. 1999), 002448 was renamed in February, 2001 to emphasize its relationship to 129S1/Sv-+p + Tyr-c Kitl Sl-J /+.]
Implementation
These new nomenclature rules should be put into effect as soon as possible, though it is recognised that this may take some time if it involves printing new literature, pricelists etc.
References
[Festing MFW. Inbred strains of mice. Mouse Genome Informatics, The Jackson Laboratory, Bar Harbor, Maine. World Wide Web (URL: http://www.informatics.jax.org/). (March, 1999).]
Simpson E. M., Linder C. C., Sargent E. E., Davisson M. T., Mobraaten L. E., and Sharp J. J. (1997) Genetic variation among 129 substrains and its importance for targeted mutagenesis in mice. Nature Genet. 16, 19-27.
Threadgill D. W., Yee D., Matin A., Nadeau J. H., and Magnuson T. (1997) Genealogy of the 129 inbred strains: 129/SvJ is a contaminated inbred strain. Mamm. Genome 8:390-393.
Note: Material in [ ] was added after publication
Table 1. New nomenclature for strain 129 mice [modified to incorporate 129S3 to 129S1 change]
| Abbreviated designation |
Full designation | Former designation | Jackson Laboratory Stock Number |
| 129P1-Lama2dy | 129P1/ReJ-Lama2dy | 129/ReJ-Lama2dy | 000641 |
|
129P1 |
129P1/ReJ | 129/ReJ | 001137 |
| 129P2 | 129P2/OlaHsd | 129/OlaHsd | na |
| 129P3 | 129P3/J | 129/J | 000690 |
| 129X1 | 129X1/SvJ | 129/SvJ | 000691 |
| 129S1 | 129S1/Sv-+p+Tyr-cKitlSl-J/+ | 129/Sv-+p+Tyr-c+MgfSl-J/+ | 000090 |
| 129S1 | 129S1/SvImJ | 129S3/SvImJ (formerly 129/SvImJ, 129/Sv-+p+Tyr-c+Mgf-Sl/J) | 002448 |
| 129S2 | 129S2/SvPas | 129/SvPas | na |
| 129S4 | 129S4/SvJae | 129/SvJae | na |
| 129S5 | 129S5/SvEvBrd | 129/SvEvBrd | na |
| 129S6 | 129S6/SvEvTac | 129/SvEvTac | na |
| 129S7 | 129S7/SvEvBrd-Hprtb-m2 | 129/SvEvBrd-Hprtb-m2 | na |
| 129S8 | 129S8/SvEv@J-Gpi1c Hprtb-m2 | 129/SvEv-Gpi1c Hprtb-m2 @J (formerly 129/SvEv -Hprtb-m2) | 002027 |
| 129T1 | 129T1/Sv-+p Tyrc-ch Ter/+@Na | 129/Sv-+p Tyrc-ch Ter/+@Na | na |
| 129T2 | 129T2/SvEms | 129/SvEms (formerly 129/SvEms-+Ter?) | 002064 |
| 129T2 | 129T2/SvEmsJ | 129/SvEmsJ (formerly 129/SvEms-+Ter?/J) | 002065 |
