Link: http://www.ncbi.nlm.nih.gov/pubmed/26510533

AbstractSend to:
Dev Growth Differ. 2015 Oct 29. doi: 10.1111/dgd.12243. [Epub ahead of print]
Expansion of the neck reconstituted the shoulder-diaphragm in amniote evolution.
Hirasawa T1, Fujimoto S1, Kuratani S1.
Author information
Abstract
The neck acquired flexibility through modifications of the head-trunk interface in vertebrate evolution. Although developmental programs for the neck musculoskeletal system have attracted the attention of evolutionary developmental biologists, how the heart, shoulder and surrounding tissues are modified during development has remained unclear. Here we show, through observation of the lateral plate mesoderm at cranial somite levels in chicken-quail chimeras, that the deep part of the lateral body wall is moved concomitant with the caudal transposition of the heart, resulting in the infolding of the expanded cervical lateral body wall into the thorax. Judging from the brachial plexus pattern, an equivalent infolding also appears to take place in mammalian and turtle embryos. In mammals, this infolding process is particularly important because it separates the diaphragm from the shoulder muscle mass. In turtles, the expansion of the cervical lateral body wall affects morphogenesis of the shoulder. Our findings highlight the cellular expansion in developing amniote necks that incidentally brought about the novel adaptive traits.

? 2015 The Authors Development, Growth & Differentiation published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Society of Developmental Biologists.

KEYWORDS:
amniote evolution; congenital diaphragmatic hernia; diaphragm; lateral plate mesoderm; neck
PMID: 26510533 [PubMed - as supplied by publisher]