Abstract
Many angiosperms prevent inbreeding through a self-incompatibility (SI) system, but the loss of SI has been frequent in their evolutionary history. The loss of SI may often lead to an increase in the selfing rate, with the purging of inbreeding depression and the ultimate evolution of a selfing syndrome, where plants have smaller flowers with reduced pollen and nectar production. In this study, we used approximate Bayesian computation (ABC) to estimate the timing of divergence between populations of the plant Linaria cavanillesii that differ in SI status and in which SI is associated with low inbreeding depression but not with a transition to full selfing or a selfing syndrome. Our analysis suggests that the mixed-mating self-compatible (SC) population may have begun to diverge from the SI populations around 2810 generation ago, a period perhaps too short for the evolution of a selfing syndrome. We conjecture that the SC population of L.cavanillesii is at an intermediate stage of transition between outcrossing and selfing.
Highlights
Hermaphrodite plants have evolved numerous strategies to prevent self-fertilization and to avoid the deleterious effects of inbreeding depression (Barrett, 2002)
Our analysis provides strong support for a scenario of ongoing gene flow between the two SI populations BER and DEN (PMigration = 0.80; robustness = 1; Table 1)
The best-supported combination of scenario and associated parameter values was able to reproduce all of the 36 observed values of summary statistics (Table S1, Figs S3 and S4), suggesting that the proposed scenario is the best among the arbitrary set of compared scenarios, but is able to explain faithfully most of the patterns of polymorphism and divergence observed among sampled natural populations of L. cavanillesii
Summary
Hermaphrodite plants have evolved numerous strategies to prevent self-fertilization and to avoid the deleterious effects of inbreeding depression (Barrett, 2002). Busch, 2005a; Guo et al, 2009; Ness et al, 2010), many partially selfing species may maintain high levels of inbreeding depression for long periods (Winn et al, 2011). This might be because inbreeding depression in such populations is so strong that no selfed individuals survive to reproductive maturity, removing any possibility for selection among selfed progeny that differ in their load of deleterious mutations (Lande et al, 1994). Our results confirm that the SC population of L. cavanillesii is very recently derived from neighbouring SI populations and represents one of the most recent transitions from outcrossing to partial selfing yet documented
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
