Meeting Abstract

59.5  Saturday, Jan. 5  Transgenerational Effects of Parental Hypoxia on Vertebrate and Invertebrate Larvae BURGGREN, W. W.; University of North Texas burggren@unt.edu

Non-genetic transgenerational modifications of offspring phenotype are increasingly evident in physiological studies. Indeed, this phenomenon is emerging as a potential source of variation in comparative physiology. Here we focus on non-genetic transgenerational transfer of morphological, physiological and behavioral traits in the zebrafish (Danio rerio) and the water flea (Daphnia magna). The experimental design was similar in both studies (Ho and Burggren, 2012; Andrewartha and Burggren, 2012). Essentially, parents were chronically exposed to hypoxia and then returned to normoxia for breeding and reproduction. A control population stayed in normoxia. The subsequently produced offspring (6-18 day old zebrafish larvae; 0-18 day old Daphnia larvae) were then exposed to severe hypoxia and their responses recorded. Additionally, physiological and metabolic traits of the larvae whose parents were exposed to hypoxia were assessed and compared with control populations. In Danio, larval offspring had longer body length when derived from adults that had been exposed to hypoxia for 2, 3 or 4 weeks. Hypoxic resistance (measured by time to loss of equilibrium) 6-18 dpf was ~15% lower in those larvae from parents that had been exposed to 1 week of chronic hypoxia, but longer exposures (2,3 or 4 weeks) significantly increased larval resistance by ~24-30%. CTMin (~39.5°C) and CTMax (~10-12 °C) were unchanged by parental hypoxic exposure. Neonatal Daphnia from hypoxic-exposed adults had a significantly smaller body mass and higher metabolic rate. These effects dissipated with further development within a brood and with subsequent broods. Parental hypoxic exposure thus can be revealed as a factor in larval phenotype through non-genetic transgenerational mechanisms.