Conserved and unique transcriptional features of pharyngeal arches in the skate (Leucoraja erinacea) and evolution of the jaw.
Christine HirschbergerVictoria A SleightKatharine E CriswellStephen J ClarkJ Andrew GillisPublished in: Molecular biology and evolution (2022)
The origin of the jaw is a long-standing problem in vertebrate evolutionary biology. Classical hypotheses of serial homology propose that the upper and lower jaw evolved through modifications 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 candidate and RNAseq/differential gene expression analyses, we find broad conservation of dorsoventral (DV) patterning mechanisms within the developing mandibular, hyoid, and gill arches of a cartilaginous fish, the skate (Leucoraja erinacea). Shared features include expression of genes encoding members of the ventralizing BMP and endothelin signaling pathways and their effectors, the joint markers nkx3.2 and gdf5 and prochondrogenic transcription factor barx1, and the dorsal territory marker pou3f3. Additionally, we find that mesenchymal expression of eya1/six1 is an ancestral feature of the mandibular arch of jawed vertebrates, whereas differences in notch signaling distinguish the mandibular and gill arches in skate. Comparative transcriptomic analyses of mandibular and gill arch tissues reveal additional genes differentially expressed along the DV axis of the pharyngeal arches, including scamp5 as a novel marker of the dorsal mandibular arch, as well as distinct transcriptional features of mandibular and gill arch muscle progenitors and developing gill buds. Taken together, our findings reveal conserved patterning mechanisms in the pharyngeal arches of jawed vertebrates, consistent with serial homology of their skeletal derivatives, as well as unique transcriptional features that may underpin distinct jaw and gill arch morphologies.
Keyphrases
- transcription factor
- gene expression
- spinal cord
- genome wide
- aortic dissection
- cone beam computed tomography
- neuropathic pain
- poor prognosis
- dna methylation
- genome wide identification
- single cell
- stem cells
- mesenchymal stem cells
- skeletal muscle
- deep learning
- dna binding
- heat shock
- epithelial mesenchymal transition
- spinal cord injury
- rna seq
- deep brain stimulation
- oxidative stress
- bioinformatics analysis