Evolutionary aspects of the development of teeth and baleen in the bowhead whale
Abstract In utero , baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs...
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crwiley:10.1111/joa.12579 2024-09-15T17:57:25+00:00 Evolutionary aspects of the development of teeth and baleen in the bowhead whale Thewissen, J. G. M. Hieronymus, Tobin L. George, John C. Suydam, Robert Stimmelmayr, Raphaela McBurney, Denise North Slope Borough NEOMED 2017 http://dx.doi.org/10.1111/joa.12579 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjoa.12579 https://onlinelibrary.wiley.com/doi/pdf/10.1111/joa.12579 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Anatomy volume 230, issue 4, page 549-566 ISSN 0021-8782 1469-7580 journal-article 2017 crwiley https://doi.org/10.1111/joa.12579 2024-09-05T05:03:58Z Abstract In utero , baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food‐collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF ‐4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF ‐4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes. Article in Journal/Newspaper baleen whale baleen whales bowhead whale Wiley Online Library Journal of Anatomy 230 4 549 566 |
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Wiley Online Library |
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English |
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Abstract In utero , baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food‐collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and lingual processes of the dental lamina represent initiation of tooth bud formation of replacement teeth. Upper tooth germs remain homodont and there is no evidence of a secondary dentition. After these germs disappear, the oral epithelium thickens to form the baleen plates, and the protein FGF ‐4 displays a signaling pattern reminiscent of baleen plates. In laboratory mammals, FGF ‐4 is not involved in the formation of hair or palatal rugae, but it is involved in tooth development. This leads us to propose that the signaling cascade that forms teeth in most mammals has been exapted to be involved in baleen plate ontogeny in mysticetes. |
author2 |
North Slope Borough NEOMED |
format |
Article in Journal/Newspaper |
author |
Thewissen, J. G. M. Hieronymus, Tobin L. George, John C. Suydam, Robert Stimmelmayr, Raphaela McBurney, Denise |
spellingShingle |
Thewissen, J. G. M. Hieronymus, Tobin L. George, John C. Suydam, Robert Stimmelmayr, Raphaela McBurney, Denise Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
author_facet |
Thewissen, J. G. M. Hieronymus, Tobin L. George, John C. Suydam, Robert Stimmelmayr, Raphaela McBurney, Denise |
author_sort |
Thewissen, J. G. M. |
title |
Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
title_short |
Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
title_full |
Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
title_fullStr |
Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
title_full_unstemmed |
Evolutionary aspects of the development of teeth and baleen in the bowhead whale |
title_sort |
evolutionary aspects of the development of teeth and baleen in the bowhead whale |
publisher |
Wiley |
publishDate |
2017 |
url |
http://dx.doi.org/10.1111/joa.12579 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjoa.12579 https://onlinelibrary.wiley.com/doi/pdf/10.1111/joa.12579 |
genre |
baleen whale baleen whales bowhead whale |
genre_facet |
baleen whale baleen whales bowhead whale |
op_source |
Journal of Anatomy volume 230, issue 4, page 549-566 ISSN 0021-8782 1469-7580 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/joa.12579 |
container_title |
Journal of Anatomy |
container_volume |
230 |
container_issue |
4 |
container_start_page |
549 |
op_container_end_page |
566 |
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1810433573116706816 |