The monogamous mating system of Peromyscus californicus as revealed by DNA fingerprinting

Summary I used DNA fingerprinting to assess mating exclusivity in Peromyscus californicus, a species presumed to be monogamous. Putative genealogical relationships were determined in the field from transfer of fluorescent pigments. The putative father was confirmed to be the genetic father for 82 offspring from 22 complete families. An additional 17 offspring from 5 families were tested in which samples from either the mother or father were not available. The offspring within each family were most likely full siblings and hence sired by only one father. An incestuous mating between brother and sister was also confirmed with DNA fingerprinting. Thus, all offspring from 28 families resulted from exclusive matings between single male and female pairs over a 2-year period. There were no instances of multiple paternity detected, and mate switches occurred only after one member of a pair disappeared. This is the first convincing demonstration of exclusive monogamy in a mammal.Offprint requests to: D.O. Ribble at his California address