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X-WR-CALNAME;VALUE=TEXT:Jenni Austiff Thesis Defense (James Hanken, Advisor)
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SUMMARY:Jenni Austiff Thesis Defense (James Hanken, Advisor)
DESCRIPTION:<!--break--><p>	<strong>Title: </strong>Development and evolution of the larval stomach of the Budgett’s Frog, <em>Lepidobatrachus </em><em>laevis</em></p><p>	<strong>Abstract: </strong>Anurans have a strongly conserved biphasic life history with extremely morphologically- and ecologically- divergent tadpole and adult phases. Tadpoles are typically aquatic, filter-feeding herbivores that transform dramatically during metamorphosis into semi-terrestrial, bulk-feeding carnivores. The gut morphology of these life phases is very constrained–tadpoles have a reduced, highly derived stomach while adult frogs have a more typical vertebrate gut with a large digestive stomach. <em>Lepidobatrachus laevis </em>tadpoles have evolved extreme larval carnivory, even cannibalism, with nearly complete ecomorphological overlap with adult frogs. Their stomachs develop peramorphically and are adult-like at hatching. This dissertation investigates the extent of the heterochronic shift and developmental mechanisms generating the adult-like tadpole stomach morphology in <em>L. laevis</em>.</p><p>	In Chapter 1, using histological examinations of microanatomy, I find that the developmental trajectory of the stomach of <em>L. laevis </em>is highly derived from the plesiomorphic state, and the development of an adult stomach morphology is completely peramorphically shifted into larval development. The stomach of <em>L. laevis</em> does not remodel at metamorphosis. In Chapter 2, I use RNA-seq to investigate the genetic mechanisms by which development of the adult-like stomach occurs, with particular focus on the role of decreased retinoic acid in mediating this developmental shift. The findings in this chapter show that modules of stomach development in <em>L. laevis</em>, including those regulated by retinoic acid, are temporally shifted to resemble stomach metamorphosis in <em>Xenopus tropicalis</em>. The evidence presented in these two chapters shows that a complete heterochronic shift has occurred in the development of <em>L. laevis</em> tadpole stomach morphology.</p><p>	<strong>Committee:</strong> James Hanken (Advisor), Elena Kramer, Mansi Srivastava, Cliff Tabin (HMS)</p>
LOCATION:Biological Laboratories Lecture Hall 1080, 16 Divinity Avenue
STATUS:CONFIRMED
DTSTART:20230519T130000Z
DTEND:20230519T130000Z
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