Evolutionary biology still faces many challenges concerning how geographic barriers,</p><p>organisms dispersal capacity and biotic and abiotic characteristics determine the patterns of gene flow and genetic variation and structure of a population. The variation observed in gene flow patterns originated from different larval dispersal abilities define important ecological and evolutionary changes during time, what makes the marine species interesting models to infer about genetic structure and local adaptation, such as the gastropod Littoraria flava. However, few information is known about the relationship between diversification, the structure of populations and the environment where they live, and as a result, which possible genes may be being selected and differentially expressed as a response to a particular environment. The present project aims to identify and annotate differentially expressed genes, through the RNA-seq approach, in L. flava samples from different environments and locations in the Brazilian rocky shore. There are expected differences in the patterns of candidate gene expression related to traits, such as ecological, physiological, morphological or development ones. In this way, we seek to provide subsidies to investigate if these alterations in expression would be involved with a local adaptation, in addition to enable the possibility of future genetic studies involving environmental disturbances, such as oceans warming and exposure</p><p>to chemicals.