A Comparative Karyotype Analysis in Haplopappus gracilis (2n=4) and H. ravenii (2n=8)

In the present investigation the karyotypes of H. gracilis (2n=4) and those of H. ravenii (2n=8) were comparatively studied.2. Chromosome 1g, the long V-shaped chromosome of H. gracilis, possessed three heterochromatic regions which indicate that this chromosome is composed of three chromosomes 1r, 2r and 3r of H. ravenii arranged in tandem order, 1r-3r-2r. Both the elimination of the centromeres from chromosomes 2r and 3r and the loss of a long euchromatic segment in the long arm of chromosome 2r might have played a role for the organization of chromosome 1g.3. Chromosome 2g, the satellite Js-shaped chromosome of H. bracilis, was presumed to compose of both chromosome 4r, the satellite js-shaped chromosome of H. ravenii, and an euchromatic segment translocated from chromosome 2r.