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Effects of oxidative stress on sex-specific gene expression in the copepod Tigriopus californicus revealed by single individual RNA-seq
- Li, Ning, Arief, Natasha, Edmands, Suzanne
- Comparative biochemistry and physiology 2019 v.31 pp. 100608
- Tigriopus californicus, algae, carotenoids, diet, females, gene expression, gene expression regulation, genes, hydrogen peroxide, males, models, oxidative stress, sequence analysis, sex chromosomes, transcription (genetics), transcriptomics, variance, yeasts
- Oxidative stress reflects the imbalance of pro-oxidants and antioxidants. Prolonged oxidative stress can induce cellular damage, diseases and aging, and the effects may be sex-specific. Tigriopus californicus has recently been proposed as an alternative model system for sex-specific studies due to the absence of sex chromosomes. In this study, we used comparative transcriptomic analyses to assess sex-specific transcriptional responses to oxidative stress. Male and female individuals were maintained separately in one of three treatments: 1) control conditions with an algae diet, 2) pro-oxidant (H2O2) conditions with an algae diet or 3) decreased antioxidant conditions (reduced carotenoids due to a yeast diet). Single individual RNA-seq was then conducted for twenty-four libraries using Ligation Mediated RNA sequencing (LM-Seq). Variance in gene expression was partitioned into 62.3% between sexes, 26.85% among individuals and 10.85% among treatments. Within each of the three treatments, expression was biased toward females. However, compared to the control treatment, males in both pro-oxidant and decreased antioxidant treatments differentially expressed more genes while females differentially expressed fewer genes but with a greater magnitude of fold change. As the first study of copepods to apply single individual RNA-seq, the findings will contribute to a better understanding of transcriptomic variation among individuals as well as sex-specific response mechanisms to oxidative stress in the absence of sex chromosomes.