Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw

The origin of the jaw is a long-standing problem in vertebrate evolution. Classical hypotheses of serial homology proposed that the upper and lower jaw evolved through modification of dorsal and ventral gill arch skeletal elements, respectively. If the jaw and gill arches are derived members of a primitive branchial series, we predict that they would share common developmental patterning mechanisms. Using RNAseq/differential gene expression analyses, we find broad conservation of dorsoventral patterning mechanisms as well as unique transcriptional features within the developing mandibular, hyoid and gill arches of a cartilaginous fish, the skate (Leucoraja erinacea).

颌骨的起源是脊椎动物演化领域长期存在的经典科学问题。系列同源性（serial homology）经典假说提出，上下颌分别通过改造背侧与腹侧的鳃弓骨骼结构演化而来。若颌骨与鳃弓均起源于原始鳃弓系列的特化成员，则二者理应共享共通的发育模式调控机制。本研究通过RNAseq/差异基因表达分析，在软骨鱼类小鳐（Leucoraja erinacea）发育中的下颌弓、舌弓与鳃弓中，发现背腹模式调控机制存在广泛保守性，同时兼具独特的转录特征。