GENETIC DIVERSITY WITHIN AND AMONG VEGETATIVE COMPATIBILITY GROUPS OFSTEREUM-SANGUINOLENTUM DETERMINED BY ARBITRARY PRIMED PCR

Genetic variation within and among vegetative compatibility groups (VC Gs) of Stereum sanguinolentum isolates was investigated with various g eographical distances. DNA fingerprints were made using the M13 core s equence 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 per centages were 42%, 30% and 0%. Average band-sharing indices (ABSIs) wi thin VCGs decreased with increasing geographical distance: for isolate s from VCG G1, ABSI was 91.3% within sample plots, 85.4% among sample plots within a country, and 79.2% among countries. Corresponding figur es for the other 15 VCGs were 97.0%, 92.7% and 80.4%, respectively. Am ong VCGs similarities were significantly lower (P < 0.001) and the tre nd of decreasing similarity with larger geographical distances was les s pronounced: ABSI within sample plots was 73.7%, among sample plots w ithin countries 73.8%, and among countries 71.1%. However, the similar ity of populations as compared within and between countries differed s ignificantly (P < 0.001), suggesting geographical differentiation betw een S. sanguinolentum populations separated by 400 km and the Baltic s ea. Calculations of G(ST) clearly indicated geographical population su bdivision within the large VCG but not among the total sample. In summ ary, the results show population structure of inbred lines within VCGs containing closely related strains in local populations and more dist ant relationships among populations.