Coombs antibody activities and Ht values in B6.Aia3, B6.Nba2, and B6 mice. Coombs antibody activities and Ht values were determined at 10 months of age, and results are expressed as MFI for Coombs antibodies and as a percentage for Ht. Mean values are indicated by horizontal lines. Each symbol represents an individual animal (10 to 18 mice in each group). • indicates B6.Aia3, B6.Nba2, and B6 male mice bearing the Yaa mutation (Aia3.Yaa, Nba2.Yaa, and Yaa, respectively); ○, B6.Aia3, B6.Nba2, and B6 female mice lacking the Yaa mutation (Aia3, Nba2, and wild type [WT], respectively).