Molecular developmental study of the mammalian middle ear evolution

我们回顾了以往关于哺乳动物中耳进化的比较形态学和分子发育研究，提出了中耳进化中最重要的问题是“哺乳动物祖先下颌区域的鼓膜是如何形成的？”（Takechi and Kuratani, 2010）。接下来，我们检查了鸡和老鼠的胚胎，以确定导致鼓膜在下颚区域的哺乳动物特异性发育事件。我们的数据表明，在哺乳动物祖先中，初级颌关节（方关节和关节关节）相对于第一个咽袋的背移导致了下颌区域的鼓膜。

We reviewed previous comparative morphological and molecular developmental studies regarding the evolution of the mammalian middle ear and proposed that the most important issue in the evolution is "How did the tympanic membrane form in the lower jaw domain in the mammalian ancestor?" (Takechi and Kuratani, 2010). We next examined chicken and mouse embryos to identify mammal-specific developmental events which led the tympanic membrane in the lower jaw domain. Our data suggested that a dorsal shift of the primary jaw joint (articulation in the quadrate and articular) with respect to the first pharyngeal pouch in the mammalian ancestor led the tympanic membrane in the lower jaw domain.