Reptiles have placodes too. But in a reptile embryo each placode switches on genes that cause only the skin cells on the back edge of the placode to grow, eventually forming scales.
爬行动物身上同样存在基板，但在胚胎阶段时，它们只会触发基板后延的皮肤细胞基因进行增殖，并最终形成鳞片。
Reptiles have placodes too. But in a reptile embryo each placode switches on genes that cause only the skin cells on the back edge of the placode to grow, eventually forming scales.
爬行动物身上同样存在基板，但在胚胎阶段时，它们只会触发基板后延的皮肤细胞基因进行增殖，并最终形成鳞片。
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