Figure 6.

Relationship between recombination and adaptation in the D. melanogaster genome. The adaptation rate of a genomic region increases with the recombination rate until a threshold value of recombination (∼2 cM/Mb) in which adaptation rate reaches an asymptote. The shaded area represents the reduction of adaptive rate due to the cost of genome linkage, whose value has been estimated for the first time at ∼27% in a North American population of D. melanogaster. r_opt is the optimal baseline value of recombination above which any detectable HRi vanishes (see text for details). Adaptation index: K_a+, rate of adaptive nonsynonymous substitution. Negative values mean fixation of deleterious mutations. Data from Castellano et al. (2016).