title: High biological species diversity in the arctic flora.
abstract: The arctic flora is considered to be impoverished, but estimates of species diversity are based on morphological assessments, which may not provide accurate counts of biological species. Here we report on crossing relationships within three diploid circumpolar plant species in the genus Draba (Brassicaceae). Although 99% of parental individuals were fully fertile, the fertility of intraspecific crosses was surprisingly low. Hybrids from crosses within populations were mostly fertile (63%), but only 8% of the hybrids from crosses within and among geographic regions (Alaska, Greenland, Svalbard, and Norway) were fertile. The frequent occurrence of intraspecific crossing barriers is not accompanied by significant morphological or ecological differentiation, indicating that numerous cryptic biological species have arisen within each taxonomic species despite their recent (Pleistocene) origin.
authors.affiliation: National Centre for Biosystematics, Natural History Museum, University of Oslo, P.O. Box 1172, Blindern NO-0318 Oslo, Norway.
authors.forename: Hanne Hegre
authors.initials: HH
authors.lastname: Grundt
authors.forename: Siri
authors.initials: S
authors.lastname: Kjølner
authors.forename: Liv
authors.initials: L
authors.lastname: Borgen
authors.forename: Loren H
authors.initials: LH
authors.lastname: Rieseberg
authors.forename: Christian
authors.initials: C
authors.lastname: Brochmann
mesh_terms: D001110:Arctic Regions; D044822:Biodiversity; D003433:Crosses, Genetic; D019143:Evolution, Molecular; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D008957:Models, Genetic; D010802:Phylogeny; D018521:Plant Physiological Phenomena; D010944:Plants / Q000235:genetics*; D011110:Polymorphism, Genetic; D013045:Species Specificity
chemical_list: D005819:Genetic Markers