Adil GÜNER, Vehbi ESER - optima

HIGH LEVELS OF GENETIC DIVERSITY CHARACTERIZE THE
NORTHWARD POSTGLACIAL COLONIZATION IN THE
WIDESPREAD CAREX NIGRA (L.) REICHARD
P. JIMÉNEZ-MEJÍAS 1,2 , M. LUCEÑO 1 , K.A. LYE 3 , G. GUSSAROVA 2,4 & C.
BROCHMANN 2
1 Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, ctra. de Utrera
km. 1, C.P. 41013, Sevilla, Spain; pjimmej@upo.es
2 National Centre for Biosystematics, Natural History Museum, University of Oslo, P.O. Box 1172 Blindern, NO-
0318 Oslo, Norway
3 Institutt for Naturforvaltning, Norwegian University of Life Sciences, 1432 Ås, Norway
4 Department of Botany, St. Petersburg State University, Universitetskaya nab. 7/9, 199036 St. Petersburg, Russia
Carex nigra is the most widespread Carex species in Europe. It occurs across Central and
North Europe, but also in the high Mediterranean mountains. In addition, it shows a typical
Amphi-Atlantic disjunction with occurrences in Iceland, Greenland and NE North America.
We used AFLPs and plastid sequences (ycf6-psbM) to study genetic polymorphism and
unravel its biogeographic history. Genetic structure analyses revealed two main genetic
groups: one covering most of the species’ range and one located in W-C the Mediterranean,
with contact areas in N-C Iberian Peninsula, Massif Central and Moroccan Atlas. The
marginal southern populations from Sicily and Rif are depauperated, while the extensive
populations from Sierra Nevada and Atlas have higher genetic diversity. Southern populations
in both genetic groups often showed higher rarity (DW) values than those from North Europe,
suggesting southern glacial refugia. High diversity was also found in W Russia, suggesting an
eastern origin of North European populations. In AMOVA analyses, 18.09% of the variation
was found among populations, but only 9.03% was explained among geographical regions.
Thus, most of the variation is found in local populations, and differentiation among
populations from the same area can be greater than among populations from remote regions.
Several populations from Fennoscandia and North America (42.8%) showed quite high gene
diversity, and some of them also had high DW values. These results suggest a more complex
postglacial history than peripheral differentiation and recolonization from few refugia,
possibly involving introgression from closely related taxa in some areas.
Keywords: AFLP, Amphi-Atlantic disjunction, biogeography, glacial refugia, ycf6-psbM
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