Integrative and Comparative Biology Advance Access originally published online on August 8, 2007
Integrative and Comparative Biology 2007 47(3):382-389; doi:10.1093/icb/icm082
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Watch-ing out for chick limb development
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4710-057 Braga, Portugal
Correspondence: 1E-mail: ipalmeirim{at}ecsaude.uminho.pt
Time control is a crucial issue during embryonic development. Nevertheless, little is known about how embryonic cells measure time. Until recently, the only molecular clock known to operate during vertebrate embryonic development was the somitogenesis clock, exclusively functioning in coordinating the precise timing of each new pair of somites formed from the presomitic mesoderm. We have recently evidenced that a similar molecular clock also underlies the timing at which autopod chondrogenic precursors are laid down to form a skeletal limb element. In addition, we herein suggest that the molecular clock is not the only parallelism that can be established between somitogenesis and limb-bud development. In an evolutionary perspective, we support the previously proposed idea that the molecular mechanisms involved in the segmentation of the body axis may have been partially reused in the mesoderm of the lateral plate, thereby allowing the emergence of paired appendages.
From the symposium "Linking Genes and Morphology in Vertebrates" presented at the annual meeting of the Society for Integrative and Comparative Biology, January 3–7, 2007, at Phoenix, Arizona.
2Present address: Instituto Gulbenkian de Ciência, Centro de Biologia do Desenvolvimento, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.