Clonality and genetic variation in Amylostereum areolatum and A. chailletii from northern Europe

Genetic variation within and between vegetative compatibility groups (VCGs) of Amylostereum areolatum (Fr.) Boid. and Amylostereum chailletii (Pers.: Fr.) Boid. isolates was investigated. DNA fingerprints were made using the M13 core sequence as a primer. A total of 53 isolates of A. areolatum and 57 isolates of A. chailletii from Lithuania, Sweden, Denmark and Great Britain were studied. In all cases isolates belonging to the same VCG showed identical DNA banding patterns, suggesting that VCGs correspond to clones. In A. areolatum the vast majority of the isolates (spread by Sirex juvencus L.) were assigned to dispersive clones, that have wide geographical distribution (i.e. the same genotypes were detected in Lithuania, Sweden and Denmark), with low genetic variation between the different clones. By contrast, A. chailletii population structure was consistent with the spread of airborne basidiospores produced by outcrossing. Only a small fraction of A. chailletii isolates studied, could be assigned to dispersal clones with a local distribution, spread by Urocerus gigas L. Overall, M13 fingerprinting detected low genetic differentiation in both species in the samples we studied.     

Development of microsatellite markers for the red‐listed wood‐decay fungus Phlebia centrifuga

Seven polymorphic microsatellite markers were developed for the wood‐decay basidiomycete Phlebia centrifuga. The primers were identified using two techniques, based on intersimple sequence repeats (ISSR) and amplified fragment length polymorphism (AFLP), respectively. The markers were screened on 27 isolates from Europe and North America. Two markers varied only on a worldwide scale, but not within Europe. The other five showed variation on both scales. These markers will now be used to characterize populations of P. centrifuga, which is red‐listed as near‐threatened in its natural habitat due to human disturbance.     

Genetic diversity within and among vegetative compatibility groups of Stereum sanguinolentum determined by arbitrary primed PCR

Genetic variation within and among vegetative compatibility groups (VCGs) of Stereum sanguinolentum isolates was investigated with various geographical distances. DNA fingerprints were made using the M13 core sequence as a primer. A total of 113 isolates from 12 plots in Sweden, Finland and Lithuania were studied. Each VCG produced a discrete group of banding patterns. Among 20 isolates from the largest VCG, G1, the incidence of identical banding patterns was 24% within a sample plot, 8% among sample plots within a country, and 0% among countries. In the other 15 VCGs that comprised two and more isolates, corresponding percentages were 42%, 30% and 0%. Average band-sharing indices (ABSIs) within VCGs decreased with increasing geographical distance: for isolates from VCG G1, ABSI was 91.3% within sample plots, 85.4% among sample plots within a country, and 79.2% among countries. Corresponding figures for the other 15 VCGs were 97.0%, 92.7% and 80.4%, respectively. Among VCGs similarities were significantly lower ( P < 0.001) and the trend of decreasing similarity with larger geographical distances was less pronounced: ABSI within sample plots was 73.7%, among sample plots within countries 73.8%, and among countries 71.1%. However, the similarity of populations as compared within and between countries differed significantly ( P < 0.001), suggesting geographical differentiation between S. sanguinolentum populations separated by 400 km and the Baltic sea. Calculations of G _ST clearly indicated geographical population subdivision within the large VCG but not among the total sample. In summary, the results show population structure of inbred lines within VCGs containing closely related strains in local populations and more distant relationships among populations.     

Evidence of a complex phylogeographic structure in the common dormouse,Muscardinus avellanarius (Rodentia: Gliridae)

This is the first mitochondrial phylogeography of the common dormouse, Muscardinus avellanarius (Linnaeus, 1758), a hibernating rodent strictly protected in Europe (Habitat Directive, annex IV; Bern Convention, annex III). The 84 individuals of M. avellanarius, sampled throughout the distributional range of the species, have been sequenced at the mitochondrial DNA gene (cytochrome b, 704 base pairs). The results revealed two highly divergent lineages, with an ancient separation around 7.7 Mya and a genetic divergence of 7.7%. Lineage 1 occurs in Western Europe (France, Belgium, and Switzerland) and Italy, and lineage 2 occurs in Central–Northern Europe (Poland, Germany, Latvia, and Lithuania), on the Balkan Peninsula, and in Turkey. Furthermore, these two lineages are subdivided into five sublineages genetically isolated with a strong geographical association. Therefore, lineage 1 branches into two further sublineages (Western European and Italian), whereas lineage 2 contained three sublineages (Central–Northern European, Turkish, and Balkan). We observed low genetic diversity within the sublineages, in contrast to the significant level of genetic differentiation between them. The understanding of genetic population structure is essential for identifying units to be conserved. Therefore, these results may have important implications for M. avellanarius conservation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 648–664.