Sex- and developmental-specific transcriptomic analyses of the Antarctic mite, Alaskozetes antarcticus, reveal transcriptional shifts underlying oribatid mite reproduction

The oribatid mite Alaskozetes antarcticus, one of the most abundant terrestrial invertebrates in Antarctica, survives extreme temperature fluctuation and desiccation, and thrives in the short growing season characteristic of this polar environment. Several aspects of the mite's ecology and physiology are well studied, but little is known about its reproduction. In this study, we utilize sex- and development-specific next-generation RNA-sequencing (RNA-seq) analyses to identify differentially regulated transcripts underlying reproduction of A. antarcticus. Pairwise comparisons between males, females, and tritonymphs revealed more than 4000 enriched transcripts based on different transcriptional levels among sexes and developmental stages. More than 500 of these enriched transcripts were differentially upregulated over 1000-fold. Many of the highly enriched and sex-specific transcripts were previously uncharacterized or have no known orthology. Of the transcripts identified, gene ontology-based analyses linked the transcriptional distinctions to differences in reproduction, chemosensation, and stress response. Our comparative approach allowed us to determine sexually dimorphic transcript expression in A. antarcticus. We anticipate that this study will provide a baseline to better understand the mechanisms that underlie reproduction in both polar and non-polar oribatid mites.