Investigating the transition from head to trunk formation in vertebrate development

脊椎动物在发育过程中是如何形成身体结构的，一直是发育生物学研究的热点问题。基本的脊椎动物身体平面图由三个区域组成：头、躯干和尾。原肠胚形成开始后，胚胎由前向后，从头到尾逐渐发育。 换句话说，脊椎动物发育中形成的第一个结构是头部，躯干/尾巴逐渐添加到胚胎的后端。人们认为躯干和尾巴是由头部组织的一部分后部化而形成的。然而，最近的研究表明，头和躯干的形成在空间和时间上是独立的，并使用不同的模式机制。然而，很少有人知道如何控制这两种不同的图案化机制的过渡。在这个过渡过程中形成的细胞产生了颈部结构，头部和躯干之间的解剖学连接。 有趣的是，颈部区域在脊椎动物进化中相对多样化（例如，在脊椎动物中出现枕骨，在鸟类和哺乳动物中颈部区域的数量变化/限制）。 因此，了解头/躯干过渡的发育机制将提供新的见解脊椎动物形态发生和进化。

How the vertebrate body plan is established during development has been a main interesting question in the field of developmental biology. The basic vertebrate body plan consists of three domains; head, trunk and tail. After the beginning of gastrulation, the embryo develops progressively from anterior to posterior, from head to tail. In other words, the first structure forming in vertebrate development is the head and the trunk/tail are progressively added to the posterior end of the embryo. It has been thought that the trunk and tail are formed by posteriorizing a part of head tissues. However, recent studies show that head and trunk are formed in a spatially and temporally independent manner and use different patterning mechanisms. However, very little is known about how the transition of the two different patterning mechanisms is controlled. The cells forming during this transition give rise to the neck structures, the anatomical junction between head and trunk. Interestingly, the neck region is relatively well diversified in vertebrate evolution (e.g. emergence of occipital bones in amniotes and number variation/restriction in the cervical region in birds and mammals, respectively). Thus, understanding the developmental mechanisms of the head/trunk transition will provide new insight into vertebrate morphogenesis and evolution.