Cytogenetic Studies of some Hypochoeris Species (Compositae) from Brazil

Abstract

Karyotypes of nine Brazilian taxa of genus Hypochoeris were studied utilizing root-tip mitotic metaphases. Two distinct groups were found. One group includes six species that showed high asymmetric bimodal karyotypes, while the second group has two species that have a karyotype similar to those observed in European species. All the species have karyotypes with 2n = 8 that are very uniform within each group, with only small morphological differences. Nucleolar organizing region and C-band patterns are shown for H. brasiliensis.

Phylogenetic relationships among species ofHypochaeris(Asteraceae, Cichorieae) based on ITS, plastidtrnLintron,trnL‐Fspacer, andmatKsequences

“…); hence, interpreting the origin and distributional history of Hypochaeris is of significance. The existing hypothesis is that species of the genus in South America have been derived from Mediterranean taxa by longdistance dispersal (Stebbins, 1971;Ruas et al, 1995;Cerbah et al, 1998). Broader sampling and more detailed character comparisons, however, are needed to test this hypothesis.…”

DAPI Banding Pattern of Chromosomes in Several Brassicaceae Species

“…The reported examples of pericentromric C-bandsin species with small chromosomes in that publication were; Vellozia pattens (Melo et al, 1997), Rollinia pulchrinervis (Morawetz, 1981), Schippia concolor (Röser, 1994), Callisia sp. (Jones & Kenton, 1984), Costus pulverulentus (Guerra, 1988), Sesbania tetraptera (Forni-Martins et al, 1994), Crepis vesicaria (Guerra, 1982), Hypochoeris brasiliensis (Ruas et al, 1995), many base-specific binding fluorochromes, AT rich chromatic regions (DAPI and Hoechst 33258) or GC rich regions (7-aminoactinomycin D and Chromomycin A3) depending on absorption and emission spectra (Schweizer, 1981;Verm & Babu, 1995). Mason (2013) clarified that the features of eukaryotic chromosomes such as shape, size and composition of proteins, DNA and RNA, and in their number and redundancy as well may differ by subjecting to many changes during the evolution, and therefore they vary between and within individual organisms.…”