title: Catching a 'hopeful monster': shepherd's purse (Capsella bursa-pastoris) as a model system to study the evolution of flower development.
abstract: Capsella is a small genus within the mustard family (Brassicaceae). Its three species, however, show many evolutionary trends also observed in other Brassicaceae (including Arabidopsis) and far beyond, including transitions from a diploid, self-incompatible, obligatory outcrossing species with comparatively large and attractive flowers but a restricted distribution to a polyploid, self-compatible, predominantly selfing, invasive species with floral reductions. All these evolutionary transitions may have contributed to the fact that Capsella bursa-pastoris (shepherd's purse) has become one of the most widely distributed flowering plants on our planet. In addition, Capsella bursa-pastoris shows a phenomenon that, although rare, could be of great evolutionary importance, specifically the occurrence of a homeotic variety found in relatively stable populations in the wild. Several lines of evidence suggest that homeotic changes played a considerable role in floral evolution, but how floral homeotic varieties are established in natural populations has remained a highly controversial topic among evolutionary biologists. Due to its close relationship with the model plant Arabidopsis thaliana, numerous experimental tools are available for studying the genus Capsella, and further tools are currently being developed. Hence, Capsella provides great opportunities to investigate the evolution of flower development from molecular developmental genetics to field ecology and biogeography, and from morphological refinements to major structural transitions.
authors.affiliation: Friedrich-Schiller-Universität Jena, Lehrstuhl für Genetik, Philosophenweg 12, D-07743 Jena, Germany.
authors.forename: Maren
authors.initials: M
authors.lastname: Hintz
authors.forename: Conny
authors.initials: C
authors.lastname: Bartholmes
authors.forename: Pia
authors.initials: P
authors.lastname: Nutt
authors.forename: Janine
authors.initials: J
authors.lastname: Ziermann
authors.forename: Steffen
authors.initials: S
authors.lastname: Hameister
authors.forename: Barbara
authors.initials: B
authors.lastname: Neuffer
authors.forename: Günter
authors.initials: G
authors.lastname: Theissen
mesh_terms: D005075:Biological Evolution; D029687:Capsella / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development*; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development*; D005801:Genes, Homeobox; D009154:Mutation; D010641:Phenotype