{"title":"On the Origin of Tentacles and Limbs in Deuterostomia","authors":"V. V. Malakhov, O. V. Ezhova","doi":"10.1134/s1063074023080047","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The paper considers the origin of segmentation, tentacles, limbs, and ciliary bands of larvae of Deuterostomia. The analysis of the expression of regulatory genes (along with the data of classical comparative anatomy) allows us to prove the homology of the pharyngeal plane of Anthozoa and the sagittal plane of triploblatic Bilateria and to confirm the origin of the coelomic segments from the peripheral gastric pockets of coelenterone. At the same time, an end-to-end homology of the segments is assumed within the Bilateria. The homology of the preoral segment and the tentacular segment in all Bilateria is emphasized. It is assumed that the ancestors of Bilateria had two circles of tentacles, labial and marginal. The marginal tentacles of the coelenterates are homologous to the metameric appendages of Bilateria, and the labial tentacles are homologous to the perioral ciliated tentacles and the ventral ciliated sole. The ciliary bands of larvae are homologous to the labial ciliated tentacles transferred to the larval stage. Possible homologues of metameric appendages and ciliated tentacles in Deuterostomia are discussed. In chordates (taking into account the “upside-down theory” of their origin), the radials of the median fin are considered as homologues of the labial tentacles, while the radials of paired fins are considered as homologues of the marginal tentacles. Two-phase expression of <i>Hox</i> genes allows us to prove the homology of tetrapod digits and fin radials of primitive fish. The similarity of the genetic mechanisms regulating the development of limbs makes it possible to stretch the threads of homology from the coelenterate tentacles to the limbs of vertebrates.</p>","PeriodicalId":49584,"journal":{"name":"Russian Journal of Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.5000,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Russian Journal of Marine Biology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1134/s1063074023080047","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MARINE & FRESHWATER BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The paper considers the origin of segmentation, tentacles, limbs, and ciliary bands of larvae of Deuterostomia. The analysis of the expression of regulatory genes (along with the data of classical comparative anatomy) allows us to prove the homology of the pharyngeal plane of Anthozoa and the sagittal plane of triploblatic Bilateria and to confirm the origin of the coelomic segments from the peripheral gastric pockets of coelenterone. At the same time, an end-to-end homology of the segments is assumed within the Bilateria. The homology of the preoral segment and the tentacular segment in all Bilateria is emphasized. It is assumed that the ancestors of Bilateria had two circles of tentacles, labial and marginal. The marginal tentacles of the coelenterates are homologous to the metameric appendages of Bilateria, and the labial tentacles are homologous to the perioral ciliated tentacles and the ventral ciliated sole. The ciliary bands of larvae are homologous to the labial ciliated tentacles transferred to the larval stage. Possible homologues of metameric appendages and ciliated tentacles in Deuterostomia are discussed. In chordates (taking into account the “upside-down theory” of their origin), the radials of the median fin are considered as homologues of the labial tentacles, while the radials of paired fins are considered as homologues of the marginal tentacles. Two-phase expression of Hox genes allows us to prove the homology of tetrapod digits and fin radials of primitive fish. The similarity of the genetic mechanisms regulating the development of limbs makes it possible to stretch the threads of homology from the coelenterate tentacles to the limbs of vertebrates.
期刊介绍：
The Russian Journal of Marine Biology was founded in 1975 by Alexey V. Zhirmunsky, member of the Russian Academy of Sciences. The Russian Journal of Marine Biology covers a wide range of research and some applied aspects of marine biology as a synthetic science related to various fields of study on marine biota and environment. It presents fundamental research on biological processes at molecular, cellular, organismal, and populational levels in marine organisms. Consideration is given to marine objects as models in life sciences. The journal also publishes papers dedicated to events in Russian and international marine biological science and the history of biology.
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