Inbred Animal Strains


There are four main genetic types of laboratory animal used in biomedical research animal breeding systems: inbred strains, mutant strains, closed colony and hybrid animals. An inbred strain is one created by at least 20 generations of brother–sister mating; members share a unique set of characteristics. Outbred animal strain is an antonym. The cloned animals are ultimate forms which are genetically identical. Congenic strain is produced from gene‐modified animals such as transgenic and knockout animals crossed to inbred strain for a precise analysis of modified genes. There are many disease model animals which are inbred to analyse the responsible gene of the target disease. For immunology, cancer research, transplantation technology and regenerative medicine, the usefulness of inbred animal strain is increased with the usage of embryonic stem (ES) and induced pluriopotent stem (iPS) cells. The quality control of inbred strain is made with genetic monitoring.

Key Concept

  • Inbred animal strain is part but main and key laboratory animals for fundamental biomedical research.

  • It is produced by brother–sister mating but its ultimate form is a cloned animal in which all of the genes are identical.

  • They are used for gene analysis and medicine as disease models.

  • There have been many incurable diseases which are caused by gene dysfunction are now treated using the fundamental knowledge found in inbred disease model animal strains.

  • The immunology and cancer research as fundamental medicine, and organ transplantation and regenerative medicine as modern medical technology have been advanced with its usage.

  • The knowledge of cell therapy will be advanced with the usage of inbred animal strain.

  • Before the application of ES and iPS cells for medical therapy, the fundamental research should be made on them.

Keywords: laboratory animal; brother–sister mating; cloned animal; gene analysis; disease model

Figure 1.

R (coefficient of relationship; squares) and F (coefficient of inbreeding; circles) of brother and sister mating.

Figure 2.

Diagram showing the production of a segregating inbred strain of mouse with chronic renal failure (ICGN/Oa).



Campbell KHS, McWhir J, Ritchie WA and Wilmut I (1996) Sheep cloned by nuclear transfer from a cultured cell line. Nature 380: 64–66.

Kato Y, Tani T, Sotomaru Y et al. (1998) Eight calves cloned from somatic cells of a single adult. Science 282: 2095–2098.

Kurosawa T, Okamoto M, Yamada K and Bing Fei Yue (1993) Nephrosis (nep): a new mouse mutation which causes albuminuria and other symptoms of nephrosis. Mouse Genome 91(4): 876–878.

Lander ES and Schork NJ (1994) Genetic Dissection of Complex Traits. Science 265(5181): 2037–2048.

Miki H, Lee J, Ogonoki N et al. (2004) Microinsemination with first‐wave round spermatids from immature male mice. Journal of Reproductive Development 50(1): 131–137.

Mizuno S, Kurosawa T, Matsumoto K et al. (1998) Hepatocyte growth factor prevents renal fibrosis and dysfunction in a mouse model of chronic renal disease. Journal of Clinical Investigation 101(9): 1827–1834.

Mizuno S, Mizuno‐Horikawa Y, Bing‐Fei Yue, Okamoto M and Kurosawa T (1999) Nephrotic mice (ICGN strain): a model of diffuse mesangial sclerosis in infantile nephrotic syndrome. American Journal of Nephrology 19: 73–82.

Nakagawa M, Koyanagi M, Tanabe K et al. (2008) Generation of induced pluripotent stem cells without Myc from mouse and human fibroblasts. Nature Biotechnology 26(1): 101–106.

Okita K, Ichisaka T and Yamanaka S (2007) Generation of germline‐competent induced pluripotent stem cells. Nature 448(7151): 313–317.

Wakayama T, Perry ACF, Zuccotti M, Johnson KR and Yanagimachi R (1998) Full‐term development of mice from enucleated oocytes injected with cumulus cell nuclei. Nature 394: 369–374.

Further Reading

Berry ML and Linder CC (2007) Breeding System: Considerations, Genetic Fundamentals, Genetic Background, and Strain Types. In: Fox JG, Barthold SW, Davisson MT et al. (eds) The Mouse in Biomedical Research. History, Wild Mice, and Genetics, 2nd edn, pp. 53–78. Academic Press.

Boschert K (1998) NetVet The Electronic Zoo Rodents. [].

Davisson MT (1994) International Committee on Standardized Genetic Nomenclature for Mice, Chairperson: Rules and guidelines for genetic nomenclature in mice. Mouse Genome 92: vii–xxxii.

Davisson MT (1996) Rules for nomenclature of inbredstrains. [].

Festing MFW (1979) InbredStrains in Biomedical Research. New York: Oxford University Press.

Festing MFW (1998) Inbredstrains of mice. [http://www.informatics.‐].

Festing MFW (1998) Inbredstrains of rats. [http://www.informatics.‐].

International Mouse Strain Resource (IMSR) (2008) [].

Lyon MF and Searle AG (1989) Genetic Variants and Strains of the Laboratory Mouse, 2nd edn. Oxford: Oxford University Press.

The National Bioresource Project for Rat in Japan (2008) [‐].

Zimmermann F, Weiss J and Reifenberg K (2000) Breeding and Assisted Reproduction Techniques. In: Krinke GJ (ed.) The Laboratory Rat, pp. 177–198. Academic Press.

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Kurosawa, Tsutomu(Sep 2009) Inbred Animal Strains. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0001442.pub2]