MacCabe J A, MacCabe A B, Abbott U K, McCarrey J R
J Exp Zool. 1975 Mar;191(3):383-94. doi: 10.1002/jez.1401910309.
In a study of the polydactylous mutation of the domestic chicken, diplopodia4, we have found that the genetic lesion affects primarily the mesoderm and only secondarily the ectoderm. The effect of this mutant mesenchyme on overlying ectodermal ridge, either mutant or normal, is to thicken the ridge preaxially, leading to increased outgrowth and preaxial polydactylism. A "zone of polarizing activity" in the normal limb-bud seems to have a role in the control of its anteroposterior polarity. We have examined diplopodia4 limb-buds for polarizing activity and found it to be normal in its activity and distribution. These results suggest that the supernumerary outgrowth in the mutant limbs result from increased ridge mainon of the polarizing zone.
在一项对家鸡多指突变——双足畸形4的研究中，我们发现该基因损伤主要影响中胚层，其次才影响外胚层。这种突变间充质对覆盖其上的外胚层嵴（无论是突变的还是正常的）的作用是使嵴在轴前增厚，导致生长增加和轴前多指畸形。正常肢芽中的“极化活性区”似乎在控制其前后极性方面发挥作用。我们检查了双足畸形4的肢芽的极化活性，发现其活性和分布是正常的。这些结果表明，突变肢体中的多余生长是由极化区嵴维持增加所致。
