Publication Date:
2022-05-25
Description:
© Macmillan Publishers Limited, 2010. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial-No
Derivative Works 3.0 Unported License. The definitive version was published in Nature Communications 1 (2010): 49, doi:10.1038/ncomms1045.
Description:
Motor innervation to the tetrapod forelimb and fish pectoral fin is assumed to share a conserved spinal cord origin, despite major structural and functional innovations of the appendage during the vertebrate water-to-land transition. In this paper, we present anatomical and embryological evidence showing that pectoral motoneurons also originate in the hindbrain among ray-finned fish. New and previous data for lobe-finned fish, a group that includes tetrapods, and more basal cartilaginous fish showed pectoral innervation that was consistent with a hindbrain-spinal origin of motoneurons. Together, these findings support a hindbrain–spinal phenotype as the ancestral vertebrate condition that originated as a postural adaptation for pectoral control of head orientation. A phylogenetic analysis indicated that Hox gene modules were shared in fish and tetrapod pectoral systems. We propose that evolutionary shifts in Hox gene expression along the body axis provided a transcriptional mechanism allowing eventual decoupling of pectoral motoneurons from the hindbrain much like their target appendage gained independence from the head.
Description:
Th is work
was supported by the National Institutes of Health and National Science Foundation.
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
Format:
video/quicktime
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