IMGT Repertoire (MH)

Here are 2 definitions (mouse specific) for consomic vs. congenic
Another definition (rat specific) for consomic vs. congenic

Here are 2 definitions (mouse specific) for consomic vs. congenic

Consomic

Two strains of mouse are referred to as consomic when they differ by one complete chromosome pair. Given that mouse has a karyotype with 21 different chromosomes (19 autosomes, X, Y), 21 consomic mouse strains are required for full coverage of mouse chromosomes by donor strains, from which one complete chromosome is introduced into the common genetic background referred to as the recipient. Chromosome substitution is achieved by six to seven times backcrossing of individuals identified as heterozygous for the selected chromosome to the recipient strain.
Consomic strains are a variation on congenic strains in which a whole chromosome - rather than one local chromosomal region - is backcrossed from a donor strain onto a recipient background (from: http://www.informatics.jax.org/silver/frame3.3.shtml). Consomic can also apply to rats - check the Charles River website (http://www.criver.com/fr-CA/Pages/home.aspx).

Congenic

A congenic strain is derived by mating mice carrying a foreign gene of interest in each succeeding generation to mice of an inbred strain. A fully congenic strain and the inbred partner are expected to be identical at all loci except for the transferred locus and a linked segment of chromosome. The size of the segment and the possibility of transferred alleles on other chromosomes depend on the number of backcross generations. A strain is usually considered congenic following 10 generations of backcrossing (N10). However, strains carrying mutations that have been backcrossed onto the background strain less than ten generations are considered incipient congenic strains and may be useful in a variety of research areas. The generation number of congenic strains is indicated in the strain detail (from: http://jaxmice.jax.org/).
Mice that have been bred to be essentially isogenic with an inbred strain except for a selected differential chromosomal segment are called congenic strains.

An excellent resource for questions like these is Lee M. Silver's book - Mouse Genetics, which can be found online here: http://www.informatics.jax.org/silver/.

Kathy Banks (e-mail 17/04/2003)
Forum for strain characterization and phenotypic data collection phenome-list@lists.informatics.jax.org

Another definition (rat specific) for consomic vs. congenic

Consomic

A consomic strain is an inbred strain of rat that contains a single entire chromosome from another strain. Incase you are interested in the nomenclature of congenic and consomic rats and mice please check http://www.rgd.mcw.edu/nomen/rules-for-nomen.shtml.

Congenic

A congenic strain is an inbred strain of rat that contains a small genetic region (ideally a single gene) from another strain, but which is otherwise identical to the original inbred strain. Congenic strains are derived by backcrossing to a parental inbred strain for at least ten generations while selecting for heterozygosity at a particular locus.

Rajni Nigam (e-mail 17/04/2003)
Forum for strain characterization and phenotypic data collection phenome-list@lists.informatics.jax.org

IMGT Repertoire (MH)

Consomic vs. congenic strains (mouse and rat)

Here are 2 definitions (mouse specific) for consomic vs. congenic

Consomic

Congenic

Another definition (rat specific) for consomic vs. congenic

Consomic

Congenic