Species selection maintains self-incompatibility.
Identifying traits that affect rates of speciation and extinction and, hence, explain differences in species diversity among clades is a major goal of evolutionary biology. Detecting such traits is especially difficult when they undergo frequent transitions between states. Self-incompatibility, the ability of hermaphrodites to enforce outcrossing, is frequently lost in flowering plants, enabling self-fertilization. We show, however, that in the nightshade plant family (Solanaceae), species with functional self-incompatibility diversify at a significantly higher rate than those without it. The apparent short-term advantages of potentially self-fertilizing individuals are therefore offset by strong species selection, which favors obligate outcrossing.
Department of Biological Sciences, University of Illinois at Chicago, 840 West Taylor Street, M/C 067, Chicago, IL 60607, USA.
Emma E
EE
Goldberg
Joshua R
JR
Kohn
Russell
R
Lande
Kelly A
KA
Robertson
Stephen A
SA
Smith
Boris
B
Igić
D005075:Biological Evolution; D005306:Fertilization / Q000502:physiology*; D049810:Genetic Speciation; D014644:Genetic Variation; D007178:Inbreeding; D010802:Phylogeny; D012641:Selection, Genetic; D019657:Solanaceae / Q000145:classification / Q000235:genetics / Q000502:physiology*