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Avian Spur Development: Abnormal Morphogenesis and Keratinization in the Scaleless (sc/sc) Mutant
K. Dale Smoak and Roger H. Sawyer
Transactions of the American Microscopical Society
Vol. 102, No. 2 (Apr., 1983), pp. 135-144
Stable URL: http://www.jstor.org/stable/3225883
Page Count: 10
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We have examined morphogenesis and biochemical differentiation of the metatarsal spur in normal and scaleless chickens. Unlike previous studies suggesting that the spur is a modified reticular scale, we find that keratins produced by the metatarsal spur are identical to those of scutate scales. Gross observations show that although the scaleless mutant develops spurs at the normal site, they are abnormal in their size, morphology, and time of appearance. Histologically, the epidermis and dermis of the spur in both normal and scaleless embryos are similar, yet electrophoretic data show that some alpha-keratins and all beta-keratins of normal spurs are absent from the epidermis of scaleless spurs. Thus, the spur's response to the scaleless gene differs from that observed for either scutate or reticulate scales, emphasizing the point that the tissue interactions that regulate morphogenesis and biochemical differentiation of the skin and its appendages may differ, depending on the structure being studied.
Transactions of the American Microscopical Society © 1983 American Microscopical Society