Regulatory constraints in the evolution of the tetrapod limb anterior-posterior polarity
Article Abstract:
The anterior to posterior (A-P) polarity of the tetrapod limb is obtained by the confined expression of Sonic hedgehog (Shh) at the posterior margin of developing early limb buds, under the control of HOX proteins encoded by gene members of both the HoxA and HoxD clusters. The limb A-P polarity is produced as a collateral effect of Hoxgene collinearity and the co-option of the trunk collinear mechanism has imposed an A-P polarity to these structures as the most parsimonious solution.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2006
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Tetrapod-like middle ear architecture in a Devonian fish
Article Abstract:
An analysis of tetrapod middle ear origins is presented that is based on a detailed study of Panderichthys, the immediate sister taxon of tetrapods. It is shown that that the spiracular region is radically transformed from osteolepiforms and represents the earliest stages in the origin of the tetrapod middle ear architecture and evolved as part of a spiracular breathing apparatus.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2006
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A uniquely specialized ear in a very early tetrapod
Article Abstract:
A uniquely specialized ear in a very early tetrapod is discussed. This represents a structurally and functionally unique modification of the tetrapod otic region, unlike anything seen in subsequent tetrapod evolution.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2003
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