Fig. 2. Gross morphological and histological analyses of Mab21l1 mutant adult mice. Adult heterozygous (A) and homozygous (B) mice, the latter lacking eyes. (C) Whole-mount view of adult eyes shows the iris and lens to be absent in a homozygous eye. (D,E) Hematoxylin and Eosin (HE) stained coronal sections of 3-month-old adult eyes. The adult Mab21l1^-/- eye (E) is much smaller than that of Mab21l1^+/- mice (D). Although a comparable lens structure is not present in the former, an optic nerve and retinal pigmented epithelium are apparent (E). (a-d) Higher magnification views (boxes in D and E). The connection between the lens-like rudiment and the cornea is abnormal in the Mab21l1^-/- case (b). Morphologically, retinal lamination and major classes of retinal cells appear in both Mab21l1^+/- and Mab21l1^-/-. However, outer and inner nuclear layers in the Mab21l1^-/- eye (d) are much thinner than in the Mab21l1^+/- counterpart (c). Adult heterozygous (F) and homozygous (G) male sex organs. The arrow indicates the small preputial gland in a homozygote. (H) Dissected male preputial glands from adult heterozygote (left) and homozygote (right) embryos. Insets show HE-stained paraffin wax sections. Overall size and intralumenal spaces (inset) in the homozygous preputial gland are reduced. co, cornea; inl, inner nuclear layer; ir, iris; lru, lens-like rudiment; on, optic nerve; onl, outer nuclear layer; pe, retinal pigmented epithelium; P, penis; Pu, pureputial gland; T, testis. Scale bars: 1mm for D,E, insets in H; 200 µm for a,b; 100 µm for c,d.