GENOME SIZE, FLUOROCHROME BANDING, AND KARYOTYPE EVOLUTION IN SOME HYPOCHOERIS SPECIES

Four South American and two European species of Hypochoeris (Asteracea e) were studied using fluorochrome banding, and genome size was determ ined by flow cytometry, in order to obtain information about microevol ution in this genus and about its primary origin. Fluorochrome banding patterns showed GC-rich repeated sequences, particularly around the n ucleolar organizer regions. Few differences appeared among the South A merican species. Nevertheless, determination of nuclear DNA content an d base composition revealed significant differences among these specie s. The phylogenetic position of Hypochoeris robertia, which has the sm allest DNA content, is discussed with regard to chromosome evolution i n this genus.