Theoretical predictions of the genomic location of sex-biased genes in aphids.

The preferred chromosomal locations of sexually antagonistic mutations (Prediction 1) are based on the simulations presented in Figure 2. Prediction 2: Predicted evolution of expression pattern of a gene bearing a sexually antagonist mutation after the evolution of a modifier that reduces the expression in the harmed sex (M, F and A refer to male, sexual female and asexual female, respectively, and the sign represents relative expression in each morph). The genomic locations of sex-biased genes (Predictions 3) were obtained by combining Predictions1 and 2. Theoretical predictions 3 were then tested with empirical data by looking at the genomic location of sex-biased genes, when considering different levels of fold-change in expression (2-, 5-, 10-fold difference). Observed number of genes for X and autosomes, frequency of X-linkage, % deviation from random expectation of X-linkage (f(X) = 0.12) and its significance (Chi-square tests) are also given.