Developmental biology: A chordate with a difference

  title={Developmental biology: A chordate with a difference},
  author={Linda Z. Holland},
Molecular studies of tunicate development show that genetic programmes for early embryonic patterning can change radically during evolution, without completely disrupting the basic chordate body plan. 

Evolutionary developmental biology and genomics

Genomics bridges the gap between evolutionary and developmental biology, and can help answer questions of the evolution of developmental mechanisms, thereby revealing contraction and expansion of the genome and suggesting mechanisms for evolution of both developmental functions and genome architecture.

Chordate roots of the vertebrate nervous system: expanding the molecular toolkit

Comparisons of developmental gene expression and neuroanatomy between vertebrates and the basal chordate amphioxus indicate that these vertebrate features were built on a foundation already present in the ancestral chordate.

Developmental Constraints on Vertebrate Genome Evolution

Genes expressed early in development in zebrafish and mouse have a more dramatic effect of knock-out or mutation and are more likely to revert to single copy after whole genome duplication, relative to genes expressed late, which supports high constraints on early stages of vertebrate development.

Ancestral Vascular Lumen Formation via Basal Cell Surfaces

It is discovered that in the invertebrate cephalochordate amphioxus, the basement membranes of endoderm and mesoderm line the lumen of the major vessels, namely aorta and heart, and that basal cell surfaces can form a vascular lumen filled with ECM.

Head organization and the head/trunk relationship in protochordates: problems and prospects.

  • T. Lacalli
  • Biology
    Integrative and comparative biology
  • 2008
The morphogenetic growth process that reestablishes symmetry in late-stage larvae can now be seen, at least in part, as a recapitulation of past evolutionary events, and this has important implications for the origin and basic organization of the brain.

Evolution of eukaryotic genome architecture: Insights from the study of a rapidly evolving metazoan, Oikopleura dioica

Analysis of the O. dioica genome suggests that non‐adaptive forces such as elevated mutation rates might influence the evolution of genome architecture and may be exploited for synthetic biology applications, such as generation of orthogonal splicing systems.

Two Rounds of Whole-Genome Duplication: Evidence and Impact on the Evolution of Vertebrate Innovations

The impact of the 2R-WGD may not be related to the immediate origin of vertebrate innovations, but to the subsequent diversification of a wide variety of complex structures that facilitated the successful radiation of vertebrates.



Chordate Evolution and Autonomous Specification of Cell Fate: The Ascidian Embryo Model

The present contribution attempts to unite the two themes by postulating that autonomous specification further enhanced the modular nature of the developing tunicate embryo and permitted natural selection to act differentially on the largely independent organ systems of larvae and paedomorphs, in what amounts to a mosaic selection pattern.

Hox cluster disintegration with persistent anteroposterior order of expression in Oikopleura dioica

It is shown that the tunicate Oikopleura dioica has a complement of nine Hox genes in which all central genes are lacking but a full vertebrate-like set of posterior genes is present.

Genome evolution and developmental constraint in Caenorhabditis elegans.

It was found that the mean rate of amino acid replacement is not significantly different between genes expressed during and after embryogenesis, however, synonymous substitution rates differed significantly between these two classes.

Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida

To study the relationships among all deuterostome groups, an alignment of more than 35,000 homologous amino acids is assembled, including new data from a hemichordate, starfish and Xenoturbella and it is concluded that chordates are monophyletic.

Urochordates are monophyletic within the deuterostomes.

A detailed phylogenetic analysis of urochordates based on comparisons of 10 new u rochordate 18S ribosomal DNA sequences with other uroChordate sequences in GenBank suggests strongly that uro chordates form a monophyletic clade within the deuterostomes.


Is retinoic acid genetic machinery a chordate innovation?

A new hypothesis is proposed in which lineage‐specific duplication and loss of RA machinery genes could be related to the morphological radiation of deuterostomes, in which this new evolutionary viewpoint argues against the hypothesis that the acquisition of gene families underlying RA metabolism and signaling was a key event for the origin of chordates.

J. R. Syst. Biol

  • J. R. Syst. Biol
  • 2000