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Fig. 3. Gas1-/- limbs display a delay in chondrogenesis and
ossification. Whole-mount Alcian Blue (for cartilage) and Alizarin Red (for
calcified bones) staining of control (con; A-F) and
Gas1-/- (-/-; A'-F') embryonic limbs (dorsal view) at the
indicated stages. In all panels, digit I is on the left, and digit V, on the
right, as labeled. Arrowheads indicate delayed cartilage condensation (A',B');
arrows, delayed or lack of phalangeal separation (C',D'); open arrows, delayed
ossification of the phalanges (F'); open arrowheads, the normal size of
ossification of the metacarpals (F,F'); m, metacarpal; p, phalange.