This C57BL/6 strain is homozygous for the age related hearing loss mutation Cdh23ahl, which on this background causes progressive hearing loss with onset after 10 months of age.
The Qa2 or Ped complex includes four similar genes. The functional (Qa2positive) and null (Qa2negative) alleles correlate with the rate of preimplantation embryo development such that Qa2positive mice are characterized by the fast Ped phenotype and Qa2negative mice, which do not express the QA2 antigen, are characterized by the slow Ped phenotype. This strain, commonly known as B6.K2, is fast Ped or Qa2positive. B6.K2 mice were developed to provide a control for B6.K1 mice (Stock No. 007958). (Warner CM, 1993; Watkins A, 2006)
This H2 congenic was developed in the mid-1970s by Dr. Lorraine Flaherty through intercross and backcross of the congenic strains, B6.A-H2-T18a and B6.AK-H2k. The H2b4 haplotype, commonly described as B6.K2, consists of Kb, Db, Qa2positive and Tlab. This strain serves as a control for (Stock No. 007958) B6.Cg-H2b3/FlaCmwJ (B6.K1) which is Qa2negative. Both strains have been backcrossed to C57BL/6 for more than 20 generations. Mice from Dr. Flaherty's colony were sent to Dr. Carol Warner at Northeastern University in 1985 and maintained as sibling matings. The colony was donated to the Repository in 2007.