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Phylogenetic Origins of Endothelium
Author(s) -
Aird William Cameron
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a20
Subject(s) - hagfish , vertebrate , biology , evolutionary biology , most recent common ancestor , endothelium , anatomy , ancestor , chordate , phylogenetics , gene , genetics , history , archaeology
Endothelial cells are found in the most distantly related modern vertebrate, the hagfish, but are absent in invertebrates, cephalochordates (e.g. amphioxus) and tunicates. The fact that the endothelium is shared by jawless and jawed vertebrates is evidence that the endothelium was present in the ancestor of these animals. The absence of endothelium in amphioxus indicates that this structure was not present in the common ancestor of cephalochordates and vertebrates, and must have evolved following the divergence of amphioxus from vertebrates, between 550 and 510 million years ago. The goal of this presentation is to discuss findings relevant to the hagfish vasculature, with emphasis on anatomy, histology, and electron microscopy. Based on these findings, we will ask which of the unique properties of the hagfish vasculature are likely to be derived, and which are ancestral. Moreover, we will address selective pressures involved in the evolution of endothelial cell heterogeneity.