Black 6 (B6NTac)


C57BL/6 Mice - B6 Inbred Mouse Strain - Taconic Biosciences
This model is impacted by a newly discovered spontaneous mutation in the Thyroglobulin (Tg) gene. It will be removed over time through selective breeding. See the Fact Sheet for more information.

C57BL/6 Background

  • Model #
  • Genotype
  • Nomenclature
  • B6-F
  • B6-M

Taconic's B6 Provides Superior Performance

One of the most used inbred mouse models, the C57BL/6 is used in nearly every research application, and it's commonly used as the genetic background for transgenic mouse models. It is also the preferred model for studying diet-induced obesity and the chronic experimental autoimmune encephalomyelitis model of multiple sclerosis.

  • Popular research applications include oncology, immunology, metabolic disease, addiction and toxicology
  • C57BL/6NTac is the preferred C57BL/6 substrain for generation of genetically engineered models, including by the Knockout Mouse Project (KOMP) and International Mouse Phenotyping Consortium (IMPC)
  • The Taconic B6 has superior reproductive performance compared to other B6 substrains: superovulated females yield a high number of embryos and males have higher sperm fertilization rates
  • The Taconic C57BL/6NTac has proven more amenable to the development of quality embryonic stem cells compared to other B6 substrains
  • Popular strain for syngeneic tumor experiments; with a suite of related strains on the same background for mechanistic studies including Rag2, Rag2/OT-I, Rag2/OT-II and many more
  • Historical data shows that hydrocephaly occurs in the C57BL/6 mouse in 0.05% of the population and may not be evident until the animal is more than two months of age.


C57BL/6 litters were received in 1991 at F151 from the NIH Animal Genetic Resource. Cesarean derived in 1991 at Taconic, a foundation colony is maintained in gnotobiotic isolators. Origin is as follows: to NIH in 1951 from Jax at F32; to Jax in 1948 from Hall.


Available at the Murine Pathogen Free™, Opportunist Free™, and Germ Free health standards. Order model #B6 for Murine Pathogen Free™ and Opportunist Free™. Order model #GF-B6 for Germ Free. Inquire about ordering mice positive or negative for Segmented Filamentous Bacteria (SFB).


  • Strain Profile: Acy1f, Aladb, Car2a, Cas1g, Cd5b, Cd72b, Cd8ab, Cd8b1b, Ce2a, Es1a, Es3a, Esda, Ggc1b, Gpi1b, Gus-sb, H6pd1b, Hbaa, Hbbs, Hc1, Idh1a, Mod1b, Mup1b, Pep3a, Pgm1a, Trfb
  • Immunology: H2b, Ptprcb, Thy1b, H2-T18b
  • Retinal Degeneration: Crb1Rd8

Coat Color Loci:

a/a, B/B, C/C





Terms of Sale and Use for Black 6 (B6NTac)

Germ Free Black 6 are sold subject to Taconic's Terms and Conditions for Taconic's Models, Products and Services and the following terms of use:

  • For-profit purchasers may not breed Germ Free Black 6 except to obtain embryos or fetuses for research use.
  • Non-profit purchasers may breed Germ Free Black 6 for use in projects at purchaser's institution and on behalf of non-profit researchers only.
  • Germ Free Black 6, progeny and materials derived from them will not be distributed to third parties.
Murine Pathogen Free™, Restricted Flora™, and Opportunist Free Black 6 mice are sold subject to Taconic's Terms and Conditions for Taconic's Models, Products and Services.

Experimental Autoimmune Encephalomyelitis (EAE) in C57BL/6NTac mice

Chart demonstrates disease incidence percentage based on 5 various groups
Representative data for Experimental Autoimmune Encephalomyelitis (EAE) in C57BL/6NTac provided by Biomodels. Download the full data package.

Historical data shows that hydrocephaly occurs in the C57BL/6 mouse in 0.05% of the population and may not be evident until the animal is more than two months of age.

C57BL/6NTac substrains carry the Crb1Rd8 mutation.Retinal degeneration 8, is a mild form of retinal degeneration that affects vision. This recessive mutation is a single base pair mutation in the Crb1 gene, Crb1Rd8 (Mehalow et al. 2003) The onset of the phenotype appears to be between 2 and 6 weeks of age (Pritchett-Corning, 2012).

C57BL/6J mice present a deletion (~17 Kbp) in the Nicotinamide Nucleotide Transhydrogenase (Nnt) gene. Nnt is a transmembrane protein that catalyzes the inter conversion of NADH and NADPH in the mitochondria. Studies suggest that the presence of Nnt is essential for mitochondrial defense against oxidative stress and for normal cellular metabolism (Huang et al. 2006). Taconic’s C57BL mice, including C57BL/6JBomTac, C57BL/6NTac and C57BL/10SgSnAiTac, or our B6D2F1 and B6129F1, do not carry the Nnt mutation which is present in C57BL/6J sub-strain.

Reproductive Data

  • Average litter size: 6-8
  • Mean # litters/female: 7
  • Mean age breeder retired: 10 months
  • Mean # days to litter: 22
For some applications, weight may be critical. For orders where weight is critical, please place orders by weight, not by age. Taconic can accept orders by weight for this model, except at the GF health standard. A minimum 3 gram span is required. All weights are weights at time of packing. Mice and rats can lose weight in transit. Orders for specific weight spans will be assessed a nominal fee. More detail on weight order policies is available.

n = 500 per sex at MPF, RF and EF health standards from all global colonies. GF mice will typically weigh slightly less than the weights above.
High and low represents mean +/- 2 standard deviations
Based on sample size, the charts above represent ~90% of the population.
All growth curves represent animals housed in our barriers, at our standard density and fed NIH31-M diet. Variations at customer facilities will alter expected growth curves.
Growth charts are provided only as a guide, if a specific weight criteria is needed please order animals by weight.

Customize this chart by clicking the legend elements, then explore download options by hovering your cursor over the down arrow to the right of the chart title.

Welcome! Tell us a little about yourself