Sex-specific transcriptome of Artemia franciscana in embryogenesis

Differences in lifespan are influenced by chromosome organization and histone dynamics. Unequal sex chromosome copy numbers impact chromatin modification levels between males and females, especially the ones involved in dosage compensation (DC). Those differences could shape sex-specific traits such as lifespan, but the mechanisms and evolutionary prevalence of this phenomenon remain incompletely understood. However, the onset and stability of DC across life stages are currently unknown. Notably, all well-understood DC mechanisms share a common feature: their establishment early in embryogenesis. In Artemia, embryonic development lasts approximately five days, ending with the hatching of free-swimming nauplii. This is followed by a juvenile stage during which the sexes are immature and visually indistinguishable. Sexually mature adults with visible male-female differences emerge at 20–25 days post-fertilization (dpf). To investigate the onset of DC, we performed low-input RNA-seq on single embryos at 1-2 dpf and 4 dpf. Those stages correspond to Blastula (1-2 dpf) and post-Gastrulation (4 dpf) stages, respectively. Each group (1-2 dpf and 4 dpf) contains six biological replicates. Sex of the embryos was determined by expressed SNPs on the sex chromosomal areas.