The effect of dosage on the transcriptional profiles becomes clearer from the clustering analysis of samples from each pesticide treatment. The gene expression was concentration dependent and showing a distinct chemical-related pattern. In dimethoate exposures, the two lower and two higher concentrations were grouped separately, whereas for atrazine and carbendazim the concentrations that effect on reproduction were more closely related. Expression profiles show distinct patterns for each pesticide, suggesting that responses occur through different molecular pathways. These different responses are depicted by the different directions in which the same genes are 2-Thiouracil affected and by the uniquely affected transcripts in each pesticide exposure. The number of GYKI-52466 common and uniquely affected transcripts is represented in the Venn diagram of Figure 3. The number of overlapping genes, as an indicative of a common response, is higher between carbendazim and dimethoate. Atrazine seems to induce a more similar response to carbendazim than to dimethoate and, in fact, only 38 transcripts were exclusively affected by this herbicide. Overall, 49 transcripts are affected by all compounds which may represent general stress responses to stress. From the 49 genes, 11 have known homologies and code for e.g. heat shock protein 90, lombricine kinase, neutral and basic amino acid transport protein or integrin-linked kinase associated serine threonine phosphatase. The seven different sets of differentially expressed genes, as presented in the Venn diagram, correspond to 3 lists of uniquely affected transcripts by each pesticide and 4 lists of transcripts shared by two or three of these compounds. Those lists were used to perform an improved gene set enrichment analysis of GO terms and evaluate the biological functions significantly affected in each case. All differentially expressed genes, with significant blast homologies, present in each of the seven lists used for this analysis can be found in Table S4. Although several genes, and consequently biological processes, were affected by two or even by the three pesticides tested, some of these transcript expressions were negatively correlated, which can be seen in the heat map with the whole gene expression profiles. From this clustering analysis it is possible to observe that effects of atrazine and carbendazim were more closely related than effects of dimethoate. The behaviour of gene expression change across the range of concentrations of each pesticide is represented in Figure 4 for some of the significant differentially expressed transcripts involved in the biological processes mentioned above. Overall, and considering all the concentrations, the herbicide atrazine was the compound that induced less gene expression changes. This is not particularly surprising given that this is a compound designed to affect mainly plant organisms. Additionally, studies in fish and human cell lines with atrazine did not reveal significant changes in gene expression. In general there was an increase in the number of affected transcripts with increasing concentrations. This tendency was also observed in a study with E. albidus exposed to Cd and Zn. On the contrary, this was not the pattern when Cu was tested in this species or phenanthrene in the collembolan Folsomia candida. Although the same effect concentrations on reproduction were tested for all pesticides, the gene expression correlation between concentrations was different depending on the pesticide. These results indicate different mechanisms underlying reductions on the reproduction rates.