Originally published as Genetics Published Articles Ahead of Print on January 21, 2007.

Genetics, Vol. 175, 1965-1973, April 2007, Copyright © 2007
doi:10.1534/genetics.106.069393

Epigenetic Mechanisms for Breakdown of Self-Incompatibility in Interspecific Hybrids

* Department of Plant Biology, Cornell University, Ithaca, New York 14853 and {dagger} Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466 Gatersleben, Germany

1 Corresponding author: Department of Plant Biology, 228 Plant Science Bldg., Cornell University, Ithaca, NY 14853.
E-mail: jbn2{at}cornell.edu

As a major agent of rapid speciation, interspecific hybridization has played an important role in plant evolution. When hybridization involves species that exhibit self-incompatibility (SI), this prezygotic barrier to self-fertilization must be overcome or lost to allow selfing. How SI, a normally dominant trait, is lost in nascent hybrids is not known, however. Here we demonstrate that hybrid self-fertility can result from epigenetic changes in expression of the S-locus genes that determine specificity in the SI response. We analyzed loss of SI in synthetic hybrids produced by crossing self-fertile and self-incompatible species in each of two crucifer genera. We show that SI is lost in the stigmas of A. thaliana–lyrata hybrids and their neo-allotetraploid derivatives and in the pollen of C. rubella–grandiflora hybrids and their homoploid progenies. Aberrant processing of S-locus receptor kinase gene transcripts as detected in Arabidopsis hybrids and suppression of the S-locus cysteine-rich protein gene as observed in Capsella hybrids are two reversible mechanisms by which SI might break down upon interspecific hybridization to generate self-fertile hybrids in nature.


Related articles in Genetics:

ISSUE HIGHLIGHTS

Genetics 2007 175: NP. [Full Text]  



This article has been cited by other articles:


Home page
Proc. Natl. Acad. Sci. USAHome page
Y.-L. Guo, J. S. Bechsgaard, T. Slotte, B. Neuffer, M. Lascoux, D. Weigel, and M. H. Schierup
Recent speciation of Capsella rubella from Capsella grandiflora, associated with loss of self-incompatibility and an extreme bottleneck
PNAS, March 31, 2009; 106(13): 5246 - 5251.
[Abstract] [Full Text] [PDF]


Home page
Mol Biol EvolHome page
M. A. Lysak, M. A. Koch, J. M. Beaulieu, A. Meister, and I. J. Leitch
The Dynamic Ups and Downs of Genome Size Evolution in Brassicaceae
Mol. Biol. Evol., January 1, 2009; 26(1): 85 - 98.
[Abstract] [Full Text] [PDF]