Much of developmental biology has focused on embryos, yet pattern formation and morphogenesis continue into post-embryonic stages and are essential for generating adult form. We still know remarkably little about these post-embryonic developmental events or the intersection of local cellular behaviors and global endocrine controls. We are using the larval-to-adult transformation of zebrafish as a system in which to understand mechanisms of post-embryonic growth and development, with relevance to human fetal and neonatal stages, as well as birth defects, regeneration and the evolution of adult form across species.
To assist in studying these later stages, we compiled a post-embryonic normal table of zebrafish development.
Thyroid hormone dependence of adult development
Thyroid hormone is essential for amphibian metamorphosis, and to see if the zebrafish larval-to-adult transformation might be similarly TH-dependent we generated transgenic fish in which we can ablate the thyroid gland. Surprisingly, hypothyroid fish continue to develop and exhibit tissue-specific effects more reminiscent of amniotes than amphibians. As just one example, scales exhibit a strong TH-dependence, being delayed and abnormally small in hypothyroid fish.
Numerous dwarfism syndromes have been described in amniotes yet the genetic bases for many of these remain unknown. To better understand requirements for normal growth and stature we have studied zebrafish mutants for Trpm7 and growth hormone 1.
Department of Biology
University of Virginia
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Charlottesville VA 22904
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