Non-Genetic Inheritance of Hypoxia Tolerance in Fishes: Dynamics and Mechanisms

University Of North Texas, Denton TX

Investigators

Abstract

This project will quantify the inheritance of tolerance to low oxygen in a model fish and then determine the tolerance mechanisms, at organismal to molecular levels, that are passed on from parents to their offspring. The investigators will not only focus on conventional, well-studied genetic mechanisms for inheritance, but will explore so-called “epigenetic” forms of inheritance that may transfer parental characteristics for only a generation or two. Such “temporary inheritance” might actually require less energy and be more beneficial to a species than the more permanent form of genetic inheritance. Bouts of low oxygen in rivers and lakes are predicted to increase as a result of both short-term climate change and global warming, and these effects may be amplified by increasing levels of human-generated pollution. Tolerance of such low-oxygen conditions by fishes has long been recognized as vital for survival of fish populations that experience short- or long-term periods of low oxygen, but surprisingly little is understood about the inheritance from the parents by the offspring of the physiology and anatomy that allows such tolerance in fishes. The information provided by this project will allow biologists to better predict, and perhaps even mitigate, the negative consequences of future episodes of low oxygen in rivers and lakes. Fully integrated into the research project are transformative, international research experiences (interactive video courses, exchange visits, and workshops involving U.S. and Mexican universities) for ethnically diverse undergraduate, graduate and post-doctoral trainees. A post-doctoral fellow and an undergraduate student will participate directly in the integrative research each year, contributing to scientific training goals. Hypoxia tolerance in fishes has long been recognized as vital for survival of populations experiencing acute or chronic environmental hypoxia. Increasingly frequent bouts of hypoxia are predicted as a result of global warming, climate stochasticity, and increasing pollution, adding urgency to developing a deeper understanding hypoxia tolerance. While we know how many adult fishes acutely and chronically respond to hypoxia, surprisingly little is known about the non-genetic (epigenetic) inheritance of the hypoxia-tolerant phenotype. Consequently, this project will quantify non-genetic inheritance of hypoxia tolerance in zebrafish as a model organism and then identify underlying mechanisms, at organismal to molecular levels, in parents and in their progeny. Specifically, this project will quantify non-genetically inherited traits that allow hypoxia tolerance, determine “wash-in” and “wash-out” (i.e., the dynamics) of hypoxia-tolerant phenotypes across multiple generations, and establish epigenetic mechanism(s) of non-genetic inheritance in subsequent generations. The potentially rapid appearance and disappearance of transgenerational non-genetically inherited phenotypes makes it crucial to understand, at organismal to molecular levels, how fish populations may cope with future hypoxia. Additionally, a strong international training component will expand a network of U.S. and Mexican universities. Participating students will gain enhanced appreciation of both international collaboration and Latino and U.S. culture through bilateral intensive workshops, interactive video coursework, and longer-term visits by research students for laboratory-based projects in both countries. This will provide a merged scientific and cultural experience that creates in trainees a first-hand knowledge of the global reach of life science research, as well as different cultural perspectives of the science experience. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.