Data from: Mating systems and selection efficacy: a test using chloroplastic sequence data in Angiosperms

Selfing is assumed to reduce selection efficacy, especially purifying
selection. This can be tested using molecular data, for example by
comparing the Dn/Ds ratio between selfing and outcrossing lineages. So
far, little evidence of relaxed selection against weakly deleterious
mutations (as inferred by a higher Dn/Ds ratio) in selfers as compared to
outcrossers has been found, contrary to the pattern often observed between
asexual and sexual lineages. However, few groups have been studied to
date. To further test this hypothesis, we compiled and analysed
chloroplastic sequence data sets in several plant groups. We found a
general trend towards relaxed selection in selfers in our data sets but
with weak statistical support. Simulations suggested that the results were
compatible with weak-to-moderate Dn/Ds ratio differences in selfing
lineages. Simple theoretical predictions also showed that the ability to
detect relaxed selection in selfers could strongly depend on the
distribution of the effects of deleterious mutations on fitness. Our
results are compatible with a recent origin of selfing lineages whereby
deleterious mutations potentially have a strong impact on population
extinction or with a more ancient origin but without a marked effect of
deleterious mutations on the extinction dynamics.