Emergence of functional and regulatory novelty at the self-incompatibility locus in Arabidopsis

Vincent Castric   
Unité Evolution, Ecologie et Paléontologie (UMR 8198 - CNRS/Université de Lille 1) - Vincent.Castric@univ-lille1.fr

(Seminar in English)

Self-incompatibility in plants of the Brassicaceae family is controlled by a highly diversified molecular lock-and-key system consisting of a large set of specific haplotypic combinations of two tightly linked genes. This system has been a textbook example of natural (balancing) selection, in the form of a strong reproductive advantage for individuals expressing rare alleles. These haplotypes also form a striking linear dominance/recessivity hierarchy, whereby most heterozygote combinations express only one self-incompatibility specificity at the phenotypic level. The question of how so many lock-and-key combinations could arise in the first place and then establish such a complex network of dominance/recessivity interactions raises a series of interesting theoretical and mechanistic problems. In this presentation, I will detail how we are currently using this simple and experimentally tractable biological system to provide insight into the broader issue of how functional and regulatory novelty can arise in natural populations.

Recent publications:

Durand E, Méheust R, Soucaze M, Goubet PM, Gallina S, Poux C, Fobis-Loisy I, Gaude T, Sarrazin A, Figeac M, Prat E, Marande W, Bergès H, Vekemans X, Billiard S, Castric V. 2014. Dominance hierarchy arising from the evolution of a complex small RNA regulatory network. Science 346: 1200-1205.

Castric, V., Billiard, S. & Vekemans, X. (2014) Trait transitions in explicit ecological and genomic contexts: plant mating systems as case studies. in: Ecological Genomics - Ecology and the Evolution of Genes and Genomes (ed. by C.R. Landry and N. Aubin-Horth), pp. 7–36. Springer.