Mutant

Genetic variation

Biology

Evolutionary biology

Botany

Gene

Gene flow

Genetics

Plant evolution

Endosperm

Genome

Genetic algorithm

Arabidopsis

Proceedings of the National Academy of Sciences

Significance Hybrid seed lethality has been recognized and addressed by a long-standing tradition of plant-breeding research. Nevertheless, its role in evolution and speciation has been underestimated. In this study, hybrid seed lethality between Arabidopsis lyrata and Arabidopsis arenosa , two model species of growing interest in the scientific community, was investigated. This study shows that endosperm defects are sufficient to explain the direction of gene flow between the two wild species, suggesting an important role of this hybridization barrier in plant speciation. In addition, we show that natural polyploidization is involved in breaking down hybridization barriers, not only establishing them, as implied by the traditional “triploid block” concept. Our data suggest that polyploidy-mediated hybrid seed rescue, long known in artificial crosses, could play an important role in plant evolution.

Endosperm-based hybridization barriers explain the pattern of gene flow between <i>Arabidopsis lyrata</i> and <i>Arabidopsis arenosa</i> in Central Europe

Endosperm-based hybridization barriers explain the pattern of gene flow between Arabidopsis lyrata and Arabidopsis arenosa in Central Europe