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Hox code in embryos of Chinese soft‐shelled turtle Pelodiscus sinensis correlates with the evolutionary innovation in the turtle
Author(s) -
Ohya Yoshie Kawashima,
Kuraku Shigehiro,
Kuratani Shigeru
Publication year - 2005
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.21027
Subject(s) - hox gene , turtle (robot) , body plan , biology , carapace , embryo , primitive streak , amniote , evolutionary biology , zoology , gene , embryogenesis , genetics , gastrulation , gene expression , vertebrate , ecology , crustacean
Turtles have the most unusual body plan of the amniotes, with a dorsal shell consisting of modified ribs. Because this morphological change in the ribs can be described as an axial‐level specific alteration, the evolution of the turtle carapace should depend on changes in the Hox code. To identify turtle‐specific changes in developmental patterns, we cloned several Hox genes from the Chinese soft‐shelled turtle, Pelodiscus sinensis , examined their expression patterns during embryogenesis, and compared them with those of chicken and mouse embryos. We detected possibly turtle‐specific derived traits in Hoxc‐6 expression, which is restricted to the paraxial part of the embryo; in the expression of Hoxa‐5 and Hoxb‐5 , the transcripts of which were detected only at the cervical level; and in Hoxc‐8 and Hoxa‐7 expression, which is shifted anteriorly relative to that of the other two amniote groups. From the known functions of the Hox orthologs in model animals, these P. sinensis ‐specific changes apparently correlate with specializations in the turtle‐specific body plan. J. Exp. Zool. (Mol. Dev. Evol.) 304B:107–118, 2005. © 2005 Wiley‐Liss, Inc.