[{"issue":"1","article_processing_charge":"No","type":"journal_article","title":"Thumbs down: A molecular-morphogenetic approach to avian digit homology","intvolume":"       322","year":"2014","publist_id":"4701","abstract":[{"lang":"eng","text":"Avian forelimb digit homology remains one of the standard themes in comparative biology and EvoDevo research. In order to resolve the apparent contradictions between embryological and paleontological evidence a variety of hypotheses have been presented in recent years. The proposals range from excluding birds from the dinosaur clade, to assignments of homology by different criteria, or even assuming a hexadactyl tetrapod limb ground state. At present two approaches prevail: the frame shift hypothesis and the pyramid reduction hypothesis. While the former postulates a homeotic shift of digit identities, the latter argues for a gradual bilateral reduction of phalanges and digits. Here we present a new model that integrates elements from both hypotheses with the existing experimental and fossil evidence. We start from the main feature common to both earlier concepts, the initiating ontogenetic event: reduction and loss of the anterior-most digit. It is proposed that a concerted mechanism of molecular regulation and developmental mechanics is capable of shifting the boundaries of hoxD expression in embryonic forelimb buds as well as changing the digit phenotypes. Based on a distinction between positional (topological) and compositional (phenotypic) homology criteria, we argue that the identity of the avian digits is II, III, IV, despite a partially altered phenotype. Finally, we introduce an alternative digit reduction scheme that reconciles the current fossil evidence with the presented molecular-morphogenetic model. Our approach identifies specific experiments that allow to test whether gene expression can be shifted and digit phenotypes can be altered by induced digit loss or digit gain."}],"date_updated":"2025-09-29T11:18:02Z","month":"01","publication":"Journal of Experimental Zoology Part B: Molecular and Developmental Evolution","oa_version":"None","language":[{"iso":"eng"}],"scopus_import":"1","_id":"2248","day":"01","date_created":"2018-12-11T11:56:33Z","volume":322,"publication_status":"published","user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","fulldoi":"https://doi.org/10.1002/jez.b.22545","department":[{"_id":"CaHe"}],"doi":"10.1002/jez.b.22545","external_id":{"isi":["000335377400001"]},"publication_identifier":{"issn":["1552-5007"]},"date_published":"2014-01-01T00:00:00Z","publisher":"Wiley-Blackwell","status":"public","author":[{"full_name":"Capek, Daniel","first_name":"Daniel","last_name":"Capek","id":"31C42484-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0001-5199-9940"},{"full_name":"Metscher, Brian","first_name":"Brian","last_name":"Metscher"},{"last_name":"Müller","full_name":"Müller, Gerd","first_name":"Gerd"}],"page":"1 - 12","isi":1,"citation":{"mla":"Capek, Daniel, et al. “Thumbs down: A Molecular-Morphogenetic Approach to Avian Digit Homology.” <i>Journal of Experimental Zoology Part B: Molecular and Developmental Evolution</i>, vol. 322, no. 1, Wiley-Blackwell, 2014, pp. 1–12, doi:<a href=\"https://doi.org/10.1002/jez.b.22545\">10.1002/jez.b.22545</a>.","ista":"Capek D, Metscher B, Müller G. 2014. Thumbs down: A molecular-morphogenetic approach to avian digit homology. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. 322(1), 1–12.","ama":"Capek D, Metscher B, Müller G. Thumbs down: A molecular-morphogenetic approach to avian digit homology. <i>Journal of Experimental Zoology Part B: Molecular and Developmental Evolution</i>. 2014;322(1):1-12. doi:<a href=\"https://doi.org/10.1002/jez.b.22545\">10.1002/jez.b.22545</a>","chicago":"Capek, Daniel, Brian Metscher, and Gerd Müller. “Thumbs down: A Molecular-Morphogenetic Approach to Avian Digit Homology.” <i>Journal of Experimental Zoology Part B: Molecular and Developmental Evolution</i>. Wiley-Blackwell, 2014. <a href=\"https://doi.org/10.1002/jez.b.22545\">https://doi.org/10.1002/jez.b.22545</a>.","apa":"Capek, D., Metscher, B., &#38; Müller, G. (2014). Thumbs down: A molecular-morphogenetic approach to avian digit homology. <i>Journal of Experimental Zoology Part B: Molecular and Developmental Evolution</i>. Wiley-Blackwell. <a href=\"https://doi.org/10.1002/jez.b.22545\">https://doi.org/10.1002/jez.b.22545</a>","ieee":"D. Capek, B. Metscher, and G. Müller, “Thumbs down: A molecular-morphogenetic approach to avian digit homology,” <i>Journal of Experimental Zoology Part B: Molecular and Developmental Evolution</i>, vol. 322, no. 1. Wiley-Blackwell, pp. 1–12, 2014.","short":"D. Capek, B. Metscher, G. Müller, Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 322 (2014) 1–12."},"quality_controlled":"1"}]