Velikost genomu a evoluční trendy rodu Hieracium L.

Abstract

In this study, 43 "main" species (Zahn) of the subgenus Hieracium and 3 species of the subgenus Chionoracium were studied karyologically and cytometrically. Triploid cyto- types predominate in the whole of Europe. Diploid cytotypes are mainly concentrated in specific areas of presumed glacial refugia in southern Europe. Chromosome counts of plants from the subgenus Chionoracium are congruent with all values published so far. The measured monoploid genome size in subgen. Hieracium correlated with the concurrently produced molecular phylogeny (ETS), which also separated two main lineages of species that correspond to their geographic distribution. Both these lineages differed significantly in genome size (Cx). On average, members of the "eastern" group had over 1 pg more DNA members of the "western" group. Some of the "main" species were marked as hybridogeneous/hybrid between the two lineages by ETS markers. The genome size of these hybridogeneous species was surprisingly higher than the average genome size of both main lineages. Intraspecies variability in genome size was found in seven species. It has been explained by the presence of populations of hybridogeneous origin, multiple polyploidization events and, in one species, turned out to be a methodical artifact. Both subgenera under study markedly...