Plant Systematics and Evolution

, Volume 241, Issue 3–4, pp 171–184 | Cite as

Karyotype evolution in South American species of Hypochaeris (Asteraceae, Lactuceae)

  • H. Weiss-Schneeweiss
  • T. F. Stuessy
  • S. Siljak-Yakovlev
  • C. M. Baeza
  • J. Parker
Article

Abstract.

The genus Hypochaeris (Asteraceae, Lactuceae) contains ten species in Europe, three in Asia, and approximately 50 in South America. Previous cytotaxonomic studies have shown two groups of taxa: (1) European species with different basic chromosome numbers and differentiated karyotypes, and (2) South American species with x=4 and uniform asymmetric and bimodal karyotypes. Karyotypic data are synthesized for South American species of Hypochaeris with new information for six Chilean species: H. acaulis, H. apargioides, H. palustris, H. spathulata, H.tenuifolia and H. thrincioides. Four main groups can be distinguished based on presence and localization of secondary constrictions – SCs (bearing Nucleolar Organizer Regions – NORs) on chromosomes 2 and 3, and 18S–25S and 5S rDNA loci number, localization, and activity. We propose karyotypic evolution of South American Hypochaeris (x=4) from H. maculata-like (x=5) European ancestors. The original South American karyotype would have possessed two SCs, one on the long arm of chromosome 2, and the other on the short arm of chromosome 3 (in terminal position). Further evolution would have involved inversion within the short arm of chromosome 3 and inactivation/loss of the SC on chromosome 2.

Keywords

FISH Hypochaeris karyotype evolution rRNA genes South America 

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Copyright information

© Springer-Verlag Wien 2003

Authors and Affiliations

  • H. Weiss-Schneeweiss
    • 1
  • T. F. Stuessy
    • 1
  • S. Siljak-Yakovlev
    • 2
  • C. M. Baeza
    • 3
  • J. Parker
    • 4
  1. 1.Department of Higher Plant Systematics and Evolution, Institute of BotanyUniversity of ViennaViennaAustria
  2. 2.Département Evolution & Systématique, UPRESA CNRS 8079Université de Paris-SudOrsay CedexFrance
  3. 3.Departamento de BotánicaUniversidad de ConcepciónConcepciónChile
  4. 4.Botanic Garden CambridgeUniversity CambridgeUK

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