Date Available
7-5-2013
Year of Publication
2013
Degree Name
Master of Science (MS)
Document Type
Master's Thesis
College
Arts and Sciences
Department/School/Program
Biology
First Advisor
Dr. S. Randal Voss
Abstract
Unlike many amphibians, the paedomorphic axolotl (Ambystoma mexicanum) rarely undergoes external morphological changes indicative of metamorphosis. However, internally, some axolotl tissues undergo cryptic metamorphic changes. A previous study examined interspecific patterns of larval brain gene expression and found that these species exhibited unique temporal expression patterns that were hypothesized to be morph specific. This thesis tested this hypothesis by examining differences in brain gene expression between juvenile (JUV), paedomorphic (PAED), and metamorphic (MET) axolotls. I identified 828 genes that were expressed differently between JUV, PAED, and MET. Expression estimates from JUV were compared to estimates from PAED and MET brains to identify genes that changed significantly during development. Genes that showed statistically equivalent expression changes across MET and PAED brains provide a glimpse at aging and maturation in an amphibian. The genes that showed statistically different expression estimates between metamorphic and paedomorphic brains provide new functional insights into the maintenance and regulation of paedomorphosis. For genes that were not commonly regulated due to aging, paedomorphs exhibited greater transcriptional similarity to juvenile than metamorphs did to juvenile. Overall, gene expression differences between metamorphic and paedomorphic development exhibit a mosaic pattern of expression as a function of aging and metamorphosis in axolotls.
Recommended Citation
Johnson, Carlena, "AXOLOTL PAEDOMORPHOSIS: A COMPARISON OF JUVENILE, METAMORPHIC, AND PAEDOMORPHIC AMBYSTOMA MEXICANUM BRAIN GENE TRANSCRIPTION" (2013). Theses and Dissertations--Biology. 13.
https://uknowledge.uky.edu/biology_etds/13
