An organism’s ability to integrate transient environmental cues experienced during development into molecular and physiological responses forms the basis for adaptive shifts in phenotypic trajectories. During temperature-dependent sex determination (TSD), thermal cues during discrete periods in development coordinate molecular changes that ultimately dictate sexual fate and contribute to patterns of inter- and intra-sexual variation. How these mechanisms interface with dynamic thermal environments in nature remains largely unknown. By deploying thermal loggers in wild nests of the American alligator (Alligator mississippiensis) over two consecutive breeding seasons, we observed that 80% of nests exhibit both male- and female-promoting thermal cues during the thermosensitive period, and of these nests, all exhibited both male- and female-promoting temperatures within the span of a single day. These observations raise a critical question— How are opposing environmental cues integrated into sexually dimorphic transcriptional programs across short temporal scales? To address this question, alligator embryos were exposed to fluctuating temperatures based on nest thermal profiles and sampled over the course of a daily thermal fluctuation. We examined the expression dynamics of upstream genes in the temperature-sensing pathway and find that post-transcriptional alternative splicing and transcript abundance of epigenetic modifier genes JARID2 and KDM6B respond rapidly to thermal fluctuations while transcriptional changes of downstream effector genes, SOX9 and DMRT1, occur on a delayed timescale. Our findings reveal how the basic mechanisms of TSD operate in an ecologically relevant context. We present a hypothetical hierarchical model based on our findings as well as previous studies, in which temperature-sensitive alternative splicing incrementally influences the epigenetic landscape to affect the transcriptional activity of key sex-determining genes.
Combined environmental stressors that an organism experiences can have both immediate and lasting consequences. In the present study, we exposed Japanese medaka (Oryzias latipes) embryos to sublethal copper sulfate (CuSO4; 0, 10, and 100 ppb) in combination with different rearing temperatures (27, 30, and 33 °C) to assess acute and latent effects on development, growth, and regenerative capacity. Embryos exposed to CuSO4 and/or higher temperatures hatched significantly earlier. At 4 months post‐exposure, fish exposed to low levels of CuSO4 during development had higher survival, whereas fish exposed to both 100 ppb CuSO4 and 33 °C temperatures had significantly lower survival. In addition, a sex‐specific effect of embryonic CuSO4 exposure was observed as female mass decreased with increasing Cu dose. We also assessed caudal fin regenerative capabilities in both embryo‐exposed fish at 4 months of age and adult medaka that were exposed to 0, 10, and 100 ppb CuSO4 at room temperature during a 14‐day trial. Whereas fin regeneration was unaffected by adult exposure to Cu, fish transiently exposed during embryogenesis displayed an initial increase in fin growth rate and an increased incidence of abnormal fin morphology following regrowth. Collectively, these data suggest that developmental Cu exposure has the potential to exert long‐lasting impacts to organismal growth, survival, and function. Environ Toxicol Chem 2022;41:748–757. © 2021 SETAC
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.