Sci. Aging Knowl. Environ., 4 February 2004
Vol. 2004, Issue 5, p. as1
[DOI: 10.1126/sageke.2004.5.as1]


B6D2F1 Mouse

James M. Harper

The author is in the Department of Pathology and Institute of Gerontology, University of Michigan, Ann Arbor, MI 48109, USA. E-mail: jmharper{at}

Key Words: inbred mouse strain • mortality • pathologies of aging

Abstract: This document contains a summary of the biological characteristics of the B6D2F1 mouse, a first-generation (F1) hybrid from a cross of a C57BL/6 female with a DBA/2 male. Included are longevity statistics calculated from data provided by the National Center for Toxicological Research.

Strain B6D2F1; this is a first-generation (F1) hybrid from a cross of a C57BL/6 female with a DBA/2 male.
Species and taxonomy House mouse, Mus musculus. Order Rodentia; family Muridae (Old World rats and mice).
Source This strain is widely available from a number of commercial sources, including the National Institute on Aging (NIA). Until recently, the NIA also supplied aged B6D2F1 individuals, but these are currently unavailable as a result of genetic contamination in the breeding colony of one of the parent strains, C57BL/6, at commercial supplier Harlan Sprague Dawley (see "Spoiled Stores"). The NIA predicts that aged B6D2F1 mice will become available again sometime in 2004. For more information, go to or contact NadonN{at}
Phenotype Brown
History and genetic background DBA mice were first bred by Little in 1909 from stock segregating for coat color; this is the oldest of all inbred strains of mice. In 1929-1930 several new substrains were established, including the widely used substrain DBA/2. The C57BL/6 strain came from stock acquired in 1921. For additional information on strain history, see Festing, 1998.

General comments. The B6D2F1 mouse is a general-purpose hybrid strain commonly used in radiation and behavioral research as well as bioassays of nutrients, drugs, and hormones. Of the parental strains, C57BL/6 is probably the most widely used of all inbred mouse strains (Festing, 1998). Unlike the BALB/c mouse strain, which has the M. m. musculus-type Y chromosome, C57BL mice carry a Y chromosome of Asian Mus musculus origin and a LINE-1 element derived from the European Mus spretus. The frequency of the LINE-1 element in C57BL mice suggests that up to 6.5% of the genome may be of M. spretus origin. Moreover, the pseudo-autosomal regions of X and Y chromosomes have a characteristic Pst I pattern of fragment sizes that is present only in the C57BL family of mouse strains.

Caveats for researchers in the field of aging. Individuals of this strain are genetically predisposed to age-related hearing loss (Erway et al., 1996). The sexually dimorphic dorsomedial nucleus of the spinal cord is affected by levels of sex steroids and exhibits a decrease in cell size after castration in this strain, as well as a decrease in the number of cells staining with thionin. This effect is age-dependent (Wagner and Clemens, 1989). Males exhibit low levels of expression of mRNAs for the cytochrome P450 2B subfamily (Jarukamjorn et al., 2000).


Life span study, Biomarkers of Aging Program (BAP), NIA, Bethesda, MD, and National Center for Toxicological Research (NCTR), Food and Drug Administration, Jefferson, AR (see Lipman et al., 1999; Turturro et al., 1999). Longevity statistics were calculated from data provided by NCTR.

Methodology (key aspects). BAP study: lifetime (up to 37 months) comparison of ad lib-fed (AL) controls with 30% calorie-restricted (CR) mice. Three rat strains (F344, BN, and BNF3F1 hybrids) and four mouse strains [C57BI/6NNia, D2 (DBA/2JNia), B6D2F1, and C3H (B6C3F1) hybrids] were included in the study. All were maintained in an SPF (specific-pathogen-free) barrier facility. Data included here are for mice fed NIH pelleted feed. Calorie restriction was initiated stepwise at 6 to 14 weeks of age and was increased over several weeks to 30%. (For experimental details, see Turturro et al., 1999.)

Statistical sample sizes (for entire life span study). Longevity statistics were calculated for 55 AL females (AL-F), 56 CR females (CR-F), 56 AL males (AL-M), and 56 CR males (CR-M).

Maximum life span in days. AL-F, 1268 (42.27 months); CR-F, 1460 (48.67 months); AL-M, 1330 (44.33 months); CR-M, 1577 (52.57 months).

Mean life span (with coefficient of variation) in days. AL-F, 861.89 (28.73 months) ± 14.09; CR-F, 1122.23 (37.41 months) ± 16.68; AL-M, 963.93 (32.13 months) ± 17.27; CR-M, 1257.50 (41.92 months) ± 10.78.

Median life span in days. AL-F, 896; CR-F, 1180; AL-M, 972; CR-M, 1313.

Time until 80% mortality in days. AL-F, 740; CR-F, 902; AL-M, 822; CR-M, 1168.

Pathologies of aging. Little or nothing is known about common pathologies of aging in this strain.

February 4, 2004
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Citation: J. M. Harper, B6D2F1 Mouse. Sci. Aging Knowl. Environ. 2004 (5), as1 (2004).

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