Abstract Detail

Molecular Ecology and Evolution

Barnard-Kubow, Karen [1], Galloway, Laura [2].

Within species reproductive isolation: does chloroplast inheritance mediate cytonuclear incompatibility?

While historically understudied, there is a growing recognition that cytonuclear incompatibilities contribute to reproductive isolation and they have even been proposed to be among the first genetic incompatibilities to arise. However, this reasoning relies to some extent on the assumption of uniparental cytoplasmic inheritance. While maternal inheritance is typical in angiosperms, hybridization may lead to an alteration of this pattern. Biparental inheritance is likely to impact the effect of cytonuclear incompatibilities as it introduces genetic variation among the organelles, allowing for selection against an incompatible organelle. We studied how biparental inheritance may mediate cytonuclear incompatibilities in Campanulastrum americanum. Recent work has shown substantial reproductive isolation among populations in this species with cytonuclear incompatibilities influencing survival. Biparental inheritance of the chloroplast may occur when crossing between genetically divergent lineages. To determine whether chloroplast inheritance is maternal in C. americanum as well as whether hybridization alters this mode of inheritance, SNP assays were used to screen F1 hybrids from genetically similar and genetically divergent crosses. Hybrid breakdown of the genetically divergent F1 hybrids was also measured to determine how chloroplast inheritance influences fitness. Moderate levels of biparental and paternal inheritance were observed in both the genetically similar and divergent crosses. In the genetically divergent crosses chloroplast inheritance strongly influenced the probability of survival. Our results show that biparental inheritance occurs at a moderate level in C. americanum regardless of genetic distance. In addition, in genetically divergent crosses, biparental inheritance may be acting as a rescue mechanism for cytonuclear incompatibilities, mediating their role for reproductive isolation in this species.

Broader Impacts:

1 - University of Virginia, Department of Biology, P.O. Box 400328, 485 McCormick Road, Charlottesville, VA, 22904-4328, USA
2 - University of Virginia, P.O. Box 400328, CHARLOTTESVILLE, VA, 22904-4328, USA

Keywords:
reproductive isolation
speciation
chloroplast genome
organelle inheritance.

Presentation Type: Oral Paper:Papers for Topics
Session: 46
Location: Newberry/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 1:30 PM
Number: 46001
Abstract ID:672
Candidate for Awards:Margaret Menzel Award