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Transcriptomic and Methylomic Analyses Show Significant Shifts in Biosynthetic Processes and Reduced Intrapopulation
Akila Harishchandra1,2, Richard T Di Giulio1, Nishad Jayasundara1
1Nicholas School of the Environment, Duke University, Durham 27708, North Carolina, United States.
Environmental Science & Technology
|November 18, 2024
Summary
Atlantic killifish rapidly evolved resistance to polycyclic aromatic hydrocarbons (PAHs), showing altered gene expression and reduced metabolic variation. This adaptation may involve trade-offs impacting susceptibility to other environmental stressors.
Area of Science:
- Environmental toxicology
- Genomics
- Ecotoxicology
Background:
- Environmental contaminants exert selection pressure, driving evolved resistance in organisms.
- Rapid adaptation can disrupt molecular and physiological homeostasis, potentially leading to fitness trade-offs.
Purpose of the Study:
- To investigate the molecular mechanisms of evolved chemical resistance in Atlantic killifish.
- To compare gene expression and methylation profiles between PAH-adapted and sensitive populations.
Main Methods:
- Comparative analysis of liver gene expression and DNA methylation profiles.
- Identification of differentially expressed, alternatively spliced, and methylated genes.
- Analysis of gene expression variation (coefficient of variation) within populations.
Main Results:
- 1607 differentially expressed and 2252 alternatively spliced genes were identified between adapted and sensitive fish.
- The aryl hydrocarbon receptor 2b (ahr2b) gene showed differential methylation, expression, and splicing, indicating its role in PAH tolerance.
- Adapted fish exhibited lower intrapopulation variation in 82% of expressed genes, particularly in bioenergetic pathways, suggesting reduced metabolic plasticity.
Conclusions:
- Rapid adaptation to polycyclic aromatic hydrocarbons (PAHs) in Atlantic killifish involves significant alterations in gene expression and reduced metabolic variation.
- The aryl hydrocarbon receptor 2b (ahr2b) gene is a key player in mediating PAH tolerance.
- Reduced physiological variation in adapted populations may represent a trade-off, potentially increasing susceptibility to other environmental stressors and warranting further investigation into population fitness.
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