Fig. 3

Positive selection shaped loqs2 evolution. A Proposed evolutionary model followed by loqs and loqs2 after the duplication events. In grey are written other common evolutionary models after any gene duplication. B Codon-based phylogenetic framework used to evaluate the selection forces acting on loqs and loqs2 and test for relaxation or intensification of selection using RELAX. The maximum likelihood phylogenetic tree was constructed with the coding sequences of loqs-D1, loqs2-D1A, loqs2-D1B and r2d2-D1 from Ae. aegypti (Aae) and Ae. albopictus (Aal). The tree is rooted at the midpoint for visualization purposes. Node values correspond to the percentages of 1000 ultra-fast bootstrap iterations. Node values > 60 are shown. Branch lengths represent nucleotide substitutions per codon site. RELAX selection intensity “k” values for each pairwise comparison between reference branches (arrow tails) and test branches (arrowheads) is represented in the tree. C Tests of positive selection based on the ω (dN/dS) metrics calculated from the phylogeny from B. The adaptive branch-site-model implemented in abSREL and the site-specific model implemented in FEL were used to test for selection among the numbered thick branches from the phylogeny in B (loqs-D1 branches are colored in grey and loqs2-D1 and loqs2-D2 are in black). aBSREL results are represented by bar plots showing the ω value and percentage of sites for each ω class. Sites with significant evidence of purifying or diversifying selection determined by FEL are colored in the 3D models of Loqs-D1, Loqs2-D1 and Loqs2-D2 from Ae. aegypti. An alignment showing the sites with significant evidence of selection is available in the Additional file 1: Fig. S4. D Ka/Ks ratio calculated from the McDonald-Kreitman test (MKT) of loqs, loqs2, Dicer-1 and Dicer-2 from an Ae. aegypti population from a forest in Senegal compared to Aedes mascarensis. Divergence time between Ae. aegypti and Ae. mascarensis was taken from [23, 27]. The complete metrics reported from the MKT are available in the Additional file 2: Table S2. Statistical significance for RELAX (p > 0.05) in B, as well as aBSREL (p > 0.05) and FEL (p > 0.1) in C were determined using likelihood ratio tests. The p-value thresholds were maintained as recommended in the documentation of each test of selection