{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T15:07:49Z","timestamp":1783955269157,"version":"3.55.0"},"reference-count":114,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2017,7,22]],"date-time":"2017-07-22T00:00:00Z","timestamp":1500681600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100004440","name":"Wellcome Trust","doi-asserted-by":"publisher","award":["202756\/Z\/16\/Z"],"award-info":[{"award-number":["202756\/Z\/16\/Z"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Genesis"],"published-print":{"date-parts":[[2018,1]]},"abstract":"<jats:title>Summary<\/jats:title><jats:p>The developing limbs of chicken embryos have served as pioneering models for understanding pattern formation for over a century. The ease with which chick wing and leg buds can be experimentally manipulated, while the embryo is still in the egg, has resulted in the discovery of important developmental organisers, and subsequently, the signals that they produce. Sonic hedgehog (Shh) is produced by mesenchyme cells of the polarizing region at the posterior margin of the limb bud and specifies positional values across the antero\u2010posterior axis (the axis running from the thumb to the little finger). Detailed experimental embryology has revealed the fundamental parameters required to specify antero\u2010posterior positional values in response to Shh signaling in chick wing and leg buds. In this review, the evolution of the avian wing and leg will be discussed in the broad context of tetrapod paleontology, and more specifically, ancestral theropod dinosaur paleontology. How the parameters that dictate antero\u2010posterior patterning could have been modulated to produce the avian wing and leg digit patterns will be considered. Finally, broader speculations will be made regarding what the antero\u2010posterior patterning of chick limbs can tell us about the evolution of other digit patterns, including those that were found in the limbs of the earliest tetrapods.<\/jats:p>","DOI":"10.1002\/dvg.23047","type":"journal-article","created":{"date-parts":[[2017,7,22]],"date-time":"2017-07-22T09:08:35Z","timestamp":1500714515000},"source":"Crossref","is-referenced-by-count":17,"title":["Evolution of antero\u2010posterior patterning of the limb: Insights from the chick"],"prefix":"10.1002","volume":"56","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2189-4536","authenticated-orcid":false,"given":"Matthew","family":"Towers","sequence":"first","affiliation":[{"name":"Department of Biomedical Science The Bateson Centre, University of Sheffield Western Bank Sheffield S10 2TN United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2017,7,22]]},"reference":[{"key":"e_1_2_4_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2004.07.023"},{"key":"e_1_2_4_3_1","doi-asserted-by":"crossref","DOI":"10.1101\/cshperspect.a028175","article-title":"Primary Cilia and Mammalian Hedgehog Signaling","volume":"9","author":"Bangs F.","year":"2017","journal-title":"Cold Spring Harbor Perspectives in Biology"},{"key":"e_1_2_4_4_1","doi-asserted-by":"publisher","DOI":"10.1038\/nature21700"},{"key":"e_1_2_4_5_1","doi-asserted-by":"publisher","DOI":"10.1242\/dev.036418"},{"key":"e_1_2_4_6_1","first-page":"7","volume-title":"University of California Press","author":"Benton M.","year":"2004"},{"key":"e_1_2_4_7_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0912818107"},{"key":"e_1_2_4_8_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.278.5338.666"},{"key":"e_1_2_4_9_1","first-page":"155","article-title":"The function of the ectodermal apical ridge and distinctive characteristics of adjacent distal mesoderm in the avian wing\u2010bud","volume":"34","author":"Cairns J. 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