Tail morphology and collagen. Tails were excised, embedded in OCT, sectioned, and stained with Hematoxylin/Eosin or Masson's Trichrome. Panel A: Representative sections stained with hematoxylin and eosin from B6 and A/J mice. Panel B: Representative sections stained with Masson's Trichrome from B6 and A/J mice. The blue color identifies the collagen. Panel C: The percentage of the collagen area (excluding center bone/cartilage) of the total tail area of each section was determined in 3–4 sections at 2–3 sites for each tail and averaged for each mouse. Values are the mean ± SEM of 4–8 mice per genotype. Symbol indicates a significant difference (*P < 0.05) between B6 mice determined by t-test.