Davidson D
J Embryol Exp Morphol. 1983 Apr;74:261-73.
During the development of the dorsal feather pattern, a wave of morphogenesis sweeps across the skin forming successive anteroposterior rows of feather primordia. The preceding paper in this series showed that the morphogenetic wave is almost immediately preceded by a wave of determination at which feathers sites are established row by row, (Davidson, 1983). The present paper reports an in vitro experimental investigation of the movement of these waves across the skin. The waves pass undisturbed across a cut made before the pattern forms. Although cultured skin does not grow and consequently forms only a few rows of primordia, the morphogenetic wave takes the same time to cross the prospective feather tissue as in vivo, indicating that the passage of this wave through cultured skin reflects its traverse of the entire pattern in vivo. These results show that the movement of the waves of determination and morphogenesis does not depend on the propagation of any signal across the skin immediately ahead of primordium formation. Their movement derives from a gradient in the temporal differentiation of the skin, established before stage 29. In this respect, the temporal control of feather development in the chick skin resembles the control of somite development in the amphibian paraxial mesoderm (Pearson & Elsdale, 1979). The present results therefore suggest that a programmed gradient of temporal differentiation across the prospective patterned tissue is a common component of the mechanisms which form regular, repetitious patterns in vertebrate embryos.
在背部羽毛图案的发育过程中，形态发生波席卷皮肤，形成连续的前后排羽毛原基。本系列的前一篇论文表明，形态发生波几乎紧接着是一排一排确定羽毛位置的决定波（戴维森，1983年）。本文报告了对这些波在皮肤中移动的体外实验研究。这些波在图案形成前进行的切割处不受干扰地通过。虽然培养的皮肤不生长，因此只形成几排原基，但形态发生波穿过预期羽毛组织的时间与在体内相同，这表明该波穿过培养皮肤反映了其在体内穿过整个图案的过程。这些结果表明，决定波和形态发生波的移动并不依赖于在原基形成之前任何信号在皮肤中的传播。它们的移动源于在第29阶段之前建立的皮肤时间分化梯度。在这方面，鸡皮肤中羽毛发育的时间控制类似于两栖类近轴中胚层中体节发育的控制（皮尔逊和埃尔斯代尔，1979年）。因此，目前的结果表明，在前体图案化组织中时间分化的程序化梯度是在脊椎动物胚胎中形成规则、重复图案的机制的一个共同组成部分。
