The Zebrafish Science Monitor Vol 3(5)
HOX GENE EXPRESSION IN TELEOST FINS AND THE ORIGIN OF VERTEBRATE DIGITSBy P. Sordino, F. van der Hoeven, and D. Duboule, Department of Zoology and Animal Biology, University of Geneva, Sciences III, Quai Ernest Ansermet 30, 1211 Geneva 4, SWITZERLAND
(Nature 375:678-681, 1995)
Hox genes are essential for growth and patterning of the tetrapod limb skeleton. Mice mutant for the Hoxd-13 gene have an important delay in morphogenesis owing to reduced proliferation. Based on the appearance of atavisms in such mice, we suggested that modifications of Hox gene regulation may have been a source of morphological variation during the evolution of tetrapod limbs. Pectoral and pelvic fins are homologous to fore- and hind-limbs, respectively. To compare the relative importance of Ho genes during fin versus limb morphogenesis, we cloned zebrafish (Danio rerio) HoxD and HoxA complex genes and analyzed their expression during fin development. The results suggest a scheme for the fin-limb transition in which the distal autopods (digits) are neomorphic structures produced by unequal proliferation of the posterior part of an ancestral appendix.
Zebrafish Science Monitor Vol 3(5)
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