Two geographic populations of Tigriopus californicus were mated to generate two parental lines and two reciprocal crosses. Samples from both sexes at both 28 days and 56 days post hatching were collected for RNA-seq. We want to develop Tigriopus californicus as a new invertebrate model system to understand the sex-specific gene expression, the role of mitochondria in aging, as well as the effects of mito-nuclear interactions on sex-specific aging.