title: The origin of digits: expression patterns versus regulatory mechanisms.
abstract: In the emerging discipline of Evo-Devo, the analysis of gene expression patterns can be deceptive without a clear understanding of the underlying regulatory strategies. Here, we use the paradigm of hand and foot evolution to argue that the consideration of the regulatory mechanisms controlling developmental gene expression is essential to resolve comparative conundrums. In this context, we discuss the adaptive relevance of evolving stepwise, distinct developmental regulatory mechanisms to build an arm, i.e., a composite structure with functional coherence.
authors.affiliation: National Research Centre Frontiers in Genetics, Department of Zoology and Animal Biology, University of Geneva, Sciences III, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland.
authors.forename: Joost M
authors.initials: JM
authors.lastname: Woltering
authors.forename: Denis
authors.initials: D
authors.lastname: Duboule
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002645:Chickens; D015509:Developmental Biology; D005121:Extremities; D005399:Fishes; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism; D008954:Models, Biological; D008957:Models, Genetic; D017434:Protein Structure, Tertiary
chemical_list: D018398:Homeodomain Proteins