Fig. 2. Maximum parsimony trees for four loci. Where multiple trees of equal length were found, disagreement was mainly limited to branching patterns within species. Because the focus here is on interspecific relationships, one tree was arbitrarily chosen that represented the majority rule interspecific topology. To reduce clutter in the tox and white gene trees, some An. gambiae and An. arabiensis sequences were excluded if they had unknown 2R karyotypes (tox) or were chosen at random (white). In the tox tree, shaded branches lead to taxa with the homokaryotypic arrangement 2Rb/b, whereas all other branches lead to taxa with the homokaryotypic arrangement 2R+^b/+^b. Labels at branch tips correspond to the entries in Table 1 in the main text, where each is preceded by G, A, Q, Ml, and Mr to denote An. gambiae, An. arabiensis, An. quadriannulatus, An. melas, and An. merus, respectively.