Figure 2.

Intrinsic incompatibilities in cichlids have been evaluated using (a) F₁ hybrid inviability (n = 52 interspecific comparisons) and (b) F₁ hybrid sex ratio distortion (n = 39 interspecific comparisons) as a function of pairwise genetic distances computed using D-loop sequences. Individual data points represent single interspecific crosses. Inviability of crosses and reports of sex ratio distortion were scored 1, while viable crosses and no reported skew in sex ratio were scored 0. Logistic regressions are depicted as black lines for F₁ hybrid inviability (a; estimate = 2.801, z = 0.581, p = 0.561) and F₁ sex ratio distortion (b; estimate = 16.330, z = 2.764, p = 0.006).