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Mouse Facts
The "laboratory mouse" originated from a mixture of M. m. domesticus, M. m. musculus, and M. m. molossius subspecies. An inbred strain of the laboratory mouse is defined as a strain that has been brother/sister mated for 20 or more consecutive generations and can be traced to a single ancestral pair. For further information about inbred strains of mice see Strains, SNPs and Polymorphisms.
Mouse Genome Length Estimates
2,716,965,481 bp Reference assembly (C57BL/6J, "golden path") length: the sum of non-redundant top level sequence regions (J:80507).
2.5 x 109 bp Mouse Genome Sequencing Consortium. 2002. Initial sequencing and comparative analysis of the mouse genome. Nature 420: 520-562.
1355.5 cM BSS and BSB crosses: Rowe LB; Barter ME; Kelmenson JA; Eppig J. 2003. Genome Res 13(1):122-33 (J:81431).
1450 cM Copeland, NG, et al. 1993. Science 62:57-66. (J:14384).
1360.9 cM Dietrich, WF et al. 1996. Nature Mar 14:380(6570)149-52 ( J:34212).
Mouse Chromosomal Size
Mapped Length represents the (MGI) estimated cM position of the most distally placed locus on that chromosome. Total Estimated Size omits centromeres and telomeres which would add, on average, ~8 Mb per chromosome or ~160 Mb to the genome. It also omits uncaptured gaps between supercontigs.
Length (cM)
Total Estimated Size (Mbp)
(NCBI build GRCm39)
198.5 195
2103.9  182
1657.8  98
1761.3  95
1859.4  91
1956.9  61
X   169
Y   91
MT 16299 bp
Total:     1441.2 2723
Codon Usage
CUTG: Codon Usage Tabulated from Genbank
Mouse Physiology
The estimates below are based on information in Biology of the Laboratory Mouse (the Staff of The Jackson Laboratory, E. Green, ed. 1966, Dover Publications, New York) and in the Mouse Phenome Database (MPD) at The Jackson Laboratory.
Note: Strain variation can affect these values significantly.
Body weight: average ~20 g; highly variable
Mouse Phenome Database: body weight
Body Temperature: ~36.9 C (in addition to strain, variables are age, sex, environmental conditions)
Lifespan: 1.3 - 3 years; highly variable
Sexual maturity: after ~4 weeks of age; highly variable
Estrus cycle frequency: every ~4-5 days
Gestation: Average 19-21 days
Litter size: usually 1-10 pups - highly variable due to genetic and environmental factors; tends to increase for the first few litters, then decrease with age
Reproductive lifespan of a female: approaches 2 years in some strains
Lactation: duration ~4 weeks
Mouse Phenome Database: reproduction data
Total serum protein: ~4-7 g/100 ml
Blood volume: ~5.5 ml per 100 g body weight
Heart rate: Adult: 632 +/- 51.3 beats per minute; Newborn: 286 +/- 56.8 beats per minute
Mouse Phenome Database: cardiovascular
Systolic pressure: 83-164 mm Hg
Blood pH: 7.3-7.4
Mouse Phenome Database: pH, blood chemistry
Respiratory rate: ~163 per minute
Mouse Phenome Database: respiratory function
Tidal volume: ~0.15 ml
Urinary Tract
Average urine output: ~1.6 ml per 24 hr
Average water intake: ~ 5 ml per 24 hr

Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
MGI 6.23
The Jackson Laboratory