Congenic AB mice: a novel means for studying the (molecular) genetics of aggression

Congenic strains (CS) of mice were established to identify genomic regions which are associated with the male behavioral trait "isolation-induced aggression" (iia). For this purpose the trait was backcrossed for 10 generations onto the genetic background of a closely related, but nonaggressive, strain. Brother/sister matings were subsequently performed for 10 generations. Genomic screening for "iia-associated" markers was performed via multilocus DNA fingerprinting with a panel of oligonucleotide probes containing simple tandem repetitive motifs. Pools of DNAs from 10 mice each were composed from inbred generations to minimize residual genetic variability in the CS. The representation of iia-associated DNA fingerprint bands was additionally ascertained by investigating the individual mouse genomes constituting the pools. The CS system may allow rational approaches to the behavioral trait "aggression," even under various experimental conditions of different environments.