Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)

One hundred and thirty-seven new chromosome counts are reported from 104 populations of 26 native South American taxa of Hypochaeris (Asteraceae, Lactuceae), together with two invasive Mediterranean species: H. glabra and H. radicata. First reports are provided for seven taxa (H. alba, H. cf. eremop...

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Detalles Bibliográficos
Autores principales: Weiss-Schneeweiss, Hanna, Stuessy, Tod F., Tremetsberger, Karin, Urtubey, Estrella, Valdebenito, Hugo A., Beck, Stephan G., Baeza, Carlos M.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2007
Materias:
Botánica
Cytotype mixture
Evolution
Polyploidy
Speciation
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/83085
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-83085
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Botánica
Cytotype mixture
Evolution
Polyploidy
Speciation
spellingShingle Botánica
Cytotype mixture
Evolution
Polyploidy
Speciation
Weiss-Schneeweiss, Hanna
Stuessy, Tod F.
Tremetsberger, Karin
Urtubey, Estrella
Valdebenito, Hugo A.
Beck, Stephan G.
Baeza, Carlos M.
Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
topic_facet Botánica
Cytotype mixture
Evolution
Polyploidy
Speciation
description One hundred and thirty-seven new chromosome counts are reported from 104 populations of 26 native South American taxa of Hypochaeris (Asteraceae, Lactuceae), together with two invasive Mediterranean species: H. glabra and H. radicata. First reports are provided for seven taxa (H. alba, H. cf. eremophila, H. caespitosa, H. hookeri, H. parodii, H. patagonica and H. pinnatifida) and one new ploidy level is reported (diploid for H. incana, so far known only as a tetraploid). Including the results of this study, the chromosomes of 39 of the c. 50 Hypochaeris species known from the New World have now been counted. Most species are diploid with 2n = 2x = 8 and have bimodal, asymmetrical karyotypes. Tetraploidy (2n = 4x = 16) is reported here for the first time in H. caespitosa. Infra-specific polyploidy (probably autopolyploidy) is reported in H. incana and H. taraxacoides, both cases including infra-populational cytotype mixtures (2x and 4x). Polyploidy is now known from eight South American Hypochaeris species (c. 16%). Basic karyotype analyses allow the placement of the newly counted taxa into previously proposed but slightly modified groupings and provide the framework for further molecular cytogenetic analyses. The reported findings suggest that chromosomal change in South American Hypochaeris, in contrast to Old World species, has not involved aneuploidy, but polyploidy and/or more subtle changes in chromosome length, perhaps via satellite DNA amplification/deletion or activity of retroelements, and rDNA reorganization.
format Articulo
Articulo
author Weiss-Schneeweiss, Hanna
Stuessy, Tod F.
Tremetsberger, Karin
Urtubey, Estrella
Valdebenito, Hugo A.
Beck, Stephan G.
Baeza, Carlos M.
author_facet Weiss-Schneeweiss, Hanna
Stuessy, Tod F.
Tremetsberger, Karin
Urtubey, Estrella
Valdebenito, Hugo A.
Beck, Stephan G.
Baeza, Carlos M.
author_sort Weiss-Schneeweiss, Hanna
title Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
title_short Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
title_full Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
title_fullStr Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
title_full_unstemmed Chromosome numbers and karyotypes of South American species and populations of Hypochaeris (Asteraceae)
title_sort chromosome numbers and karyotypes of south american species and populations of hypochaeris (asteraceae)
publishDate 2007
url http://sedici.unlp.edu.ar/handle/10915/83085
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