Genetical studies on the skeleton of the mouse XXXII. The Development of Shaker with Syndactylism

Abstract

1. The first known effect of the gene for shaker with syndactylism (sy) in the mouse is a reduction, both preaxial and postaxial, of the foot plates at the 12½-day stage. This reduction forces the blastemata of digits 2, 3 and 4 to be laid down more nearly parallel to each other, with a subsequent tendency for adjacent blastemata to coalesce with each other. The possibility is considered that this essentially quantitative reduction of the foot plate material may itself be the consequence of some more specific and qualitative (but hitherto undiscovered) change in the limb buds.2. The physiological connexion between syndactylism and the systemic changes in the cartilaginous and osseous skeleton which arise later in sy/sy mice remains obscure.