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 and is correlated with the rate of preimplantation embryo development. Qa2positive mice are characterized by the fast Ped phenotype; Qa2negative mice, which do not express the QA2 antigen, are characterized by the slow Ped phenotype. This strain, commonly known as B6.K1, is slow Ped or Qa2negative. B6.K1 females have longer gestation times and smaller litter sizes than the control B6.K2 (Stock No. 007959) females. (Warner CM, 1993) At birth, B6.K1 pups are slighter lighter than B6.K2 pups, but they exhibit an accelerated growth, and by week 6 both male and female B6.K1 mice are significantly heavier than B6.K2 mice. (Watkins A, 2006) At 21 weeks of age, B6.K1 females exhibit elevated systolic blood pressure, and both sexes exhibit elevated serum angiotensin-converting enzyme (ACE) activity. (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 H2b3 haplotype, commonly described as B6.K1, consists of Kb, Db, Qa2negative and Tlab. The control strain, (Stock No. 007959) B6.Cg-H2b4/FlaCmwJ (B6.K2), was generated in a similar fashion, and is Qa2positive. 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.