Nuclear ribosomal DNA sequence polymorphism and hybridization in checker mallows (Sidalcea, Malvaceae)

Andreasen, Katarina; Baldwin, Bruce G.

doi:10.1016/s1055-7903(03)00136-2

Cited by 46 publications

(25 citation statements)

References 37 publications

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“…tamarense and A. catenella from the China Sea could not be differentiated using ITS sequence, since both of them displayed ambiguity in certain positions, which was verified by intragenomic nucleotide polymorphism. Polymorphism was also reported in the ITS region of the Japanese A. tamarense (Adachi et al, 1996) and a diatom, Pseudo-nitzschia delicatesima (Orsini et al, 2004), which might be caused by introgression (Andreasen and Baldwin, 2003) or hybridization (Soltis et al, 1995). The homogeneity of the ITS sequence in the tamarensis complex from China suggested that no introduction has occurred, while A. tamarense and A. catenella in Japan showed significant ITS sequence variation at the interspecific level (Adachi et al, 1996).…”

Section: Discussionmentioning

confidence: 85%

Comparative studies on morphology, ITS sequence and protein profile of Alexandrium tamarense and A. catenella isolated from the China Sea

Wang

Lin

Gu³

et al. 2008

Harmful Algae

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Section: Discussionmentioning

confidence: 85%

Comparative studies on morphology, ITS sequence and protein profile of Alexandrium tamarense and A. catenella isolated from the China Sea

Wang

Lin

Gu³

et al. 2008

Harmful Algae

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“…To investigate this problem further, two polymorphic samples were cloned for both ITS and ETS (for cloning methods see Andreasen and Baldwin 2003a). Adding these clones to the analyses did not change the tree topology.…”

Section: Resultsmentioning

confidence: 99%

“…25 species of annuals and perennials. The genus displays complex patterns of morphological variation and hybridization probably has been involved in the evolution of the group (Andreasen and Baldwin 2003a). Considering the difficulty of interpreting patterns of morphological variation in the genus, Sidalcea is especially interesting to investigate from a conservation perspective.…”

Section: Introductionmentioning

confidence: 99%

Implications of molecular systematic analyses on the conservation of rare and threatened taxa: Contrasting examples from Malvaceae

Andreasen

2005

Conserv Genet

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Systematic research provides essential evidence for setting conservation priorities for rare and endangered taxa. Phylogenetic analyses can identify cryptic, genetically distinct lineages as well as actively interbreeding, and hence, non-distinctive lineages earlier perceived as separate taxa. A major aim of this study was to identify genetically distinct, rare lineages within two Malvaceae sister-genera, Sidalcea and Eremalche. The focus was two taxon-pairs each consisting of one rare and one more common taxon. The results demonstrate that even within two closely related genera, with a large number of rare taxa, molecular phylogenetic analyses can reveal contrasting degrees of evolutionary divergence and thus contrasting conservation implications for threatened taxa. Contrary to expectations, the substitution rate in the nuclear ribosomal transcribed spacers for annual Eremalche did not correspond to the faster evolutionary rate of annuals -compared to perennials -detected earlier within Sidalcea. Branch lengths in the (annual) Eremalche clade were shorter than those of annual members of Sidalcea. The phylogenetic analyses showed that the rare and endangered S. keckii and E. kernensis each are most closely related to a common species that has been regarded as insufficiently distinct to warrant separate taxonomic status. An additional aim of the study was to test the utility of the Phylogenetic Diversity (PD) measure to formalize the procedure of prioritizing conservation efforts. The measure demonstrated S. keckii (but not E. kernensis) to be genetically distinct from its closest relative and a good candidate for conservation. The PD measure was earlier used for assessing conservation priorities for areas, but proved useful to more objectively suggest conservation priorities among threatened taxa. Because this measure is calculated directly from the data, it retains more character information and gives a better representation of genetic diversity than other measures relying on tree topologies.

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“…However, in the case of suppression of the last mentioned mechanism, and thus retention of two (or more) divergent ITS copies within one genome, this marker may prove to be highly informative with respect to the hybridization history. Indeed, many case-studies documented a hybridogeneous origin of polyploid taxa using multicopy ITS or ETS (external transcribed spacer) nrDNA markers Sang et al, 1995;Campbell et al, 1997;Andreasen and Baldwin, 2003;Fehrer et al, 2009). In addition to biparentally inherited polymorphism assessed by nuclear markers, incongruencies between nuclear and plastid phylogenies may indicate reticulation event(s) (Rieseberg and Soltis and Kuzoff, 1995).…”

Section: Introductionmentioning

confidence: 99%

Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)

Mráz

Garcia‐Jacas

Gex-Fabry

et al. 2012

Molecular Phylogenetics and Evolution

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a b s t r a c tSpotted knapweed (Centaurea stoebe) occurs from Western Asia to Western Europe both as diploid and tetraploid cytotypes, predominantly in single-cytotype populations with higher frequency of diploid populations. Interestingly, only tetraploids have been recorded so far from its introduced range in North America where they became highly invasive.We performed phylogenetic and network analyses of more than 40 accessions of the C. stoebe and C. paniculata groups and other related taxa using cloned internal transcribed spacer (ITS) and sequences of the chloroplast trnT-trnL and atpBrbcL regions to (i) assess the evolutionary origin of tetraploid C. stoebe s.l., and (ii) uncover the phylogeny of the C. stoebe group. Both issues have not been studied so far and thus remained controversial.Cloned ITS sequences showed the presence of two slightly divergent ribotypes occurring in tetraploid cytotype, while only one major ribotype was present in diploid C. stoebe s.str. This pattern suggests an allopolyploid origin of tetraploids with contribution of the diploid C. stoebe s.str. genome. Although we were not able to detect the second parental taxon, we hypothesize that hybridization might have triggered important changes in morphology and life history traits, which in turn may explain the colonization success of the tetraploid taxon. Bayesian relaxed clock estimations indicate a relatively recent -Pleistocene origin of the tetraploid C. stoebe s.l. Furthermore, our analyses showed a deep split between the C. paniculata and C. stoebe groups, and a young diversification of the taxa within the C. stoebe group. In contrast to nrDNA analyses, the observed pattern based on two cpDNA regions was inconclusive with respect to the origin and phylogeny of the studied taxa, most likely due to shared ancient polymorphism and frequent homoplasies.

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Nuclear ribosomal DNA sequence polymorphism and hybridization in checker mallows (Sidalcea, Malvaceae)

Cited by 46 publications

References 37 publications

Comparative studies on morphology, ITS sequence and protein profile of Alexandrium tamarense and A. catenella isolated from the China Sea

Comparative studies on morphology, ITS sequence and protein profile of Alexandrium tamarense and A. catenella isolated from the China Sea

Implications of molecular systematic analyses on the conservation of rare and threatened taxa: Contrasting examples from Malvaceae

Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)

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