The Evolution of Haploid Chromosome Numbers in the Sunflower Family

Mota, Lucie; Torices, Rubén; Loureiro, João

doi:10.1093/gbe/evw251

Cited by 24 publications

(17 citation statements)

References 67 publications

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“…In this work, hypothesized base numbers for each of the 36 main clades were superimposed on the backbone phylogeny provided by [79] and two main patterns of karyotype change emerged, (1) polyploidy is common in Asteraceae and occurs in most major clades and (2) descending dysploid events (in contrast to the rarer increasing dysploidy) are widespread across major lineages. Later on, [80], using explicit models of chromosome evolution, corroborated previous inferences and suggested that karyological evolution has been a very dynamic process in Asteraceae mainly shaped by polyploidy and descending dysploidy scenarios.…”

Section: The Long Evolutionary History Of Asteraceae May Have Erased Phylogenetic Signals Of Itr Sitessupporting

confidence: 74%

“…Altogether, our data suggest that in Asteraceae the dynamics of ITR formation is too fast or labile to trace the complex karyological evolution that has been hypothesized to occur since the early diversification events in the family [75,80]. Further, part of such lability could be due to other types of karyological changes that erased previous ITR signs inconsistently across lineages.…”

Section: Are Centromeric Itr Signals Remnants Of Dysploidy In Asteraceae?mentioning

confidence: 77%

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Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae

Maravilla

Rosato

Álvarez

et al. 2021

Plants

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Tandem repeats of telomeric-like motifs at intra-chromosomal regions, known as interstitial telomeric repeats (ITR), have drawn attention as potential markers of structural changes, which might convey information about evolutionary relationships if preserved through time. Building on our previous work that reported outstanding ITR polymorphisms in the genus Anacyclus, we undertook a survey across 132 Asteraceae species, focusing on the six most speciose subfamilies and considering all the ITR data published to date. The goal was to assess whether the presence, site number, and chromosomal location of ITRs convey any phylogenetic signal. We conducted fluorescent in situ hybridization (FISH) using an Arabidopsis-type telomeric sequence as a probe on karyotypes obtained from mitotic chromosomes. FISH signals of ITR sites were detected in species of subfamilies Asteroideae, Carduoideae, Cichorioideae, Gymnarhenoideae, and Mutisioideae, but not in Barnadesioideae. Although six small subfamilies have not yet been sampled, altogether, our results suggest that the dynamics of ITR formation in Asteraceae cannot accurately trace the complex karyological evolution that occurred since the early diversification of this family. Thus, ITRs do not convey a reliable signal at deep or shallow phylogenetic levels and cannot help to delimitate taxonomic categories, a conclusion that might also hold for other important families such as Fabaceae.

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Section: The Long Evolutionary History Of Asteraceae May Have Erased Phylogenetic Signals Of Itr Sitessupporting

confidence: 74%

Section: Are Centromeric Itr Signals Remnants Of Dysploidy In Asteraceae?mentioning

confidence: 77%

Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae

Maravilla

Rosato

Álvarez

et al. 2021

Plants

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“…Polyploidy has long been recognised as a frequent mechanism in Asteraceae (Mota et al . and references therein) and the frequency of polyploid species observed for the family, although low for the 1 st approach, was fairly high for the Iberian Peninsula and Andalusia (46.0% and 44.1%, respectively), with genera such has Hieracium L., Leucanthemum Mill., Senecio L., Taraxacum Zinn, Centaurea L. and Artemisia L. having numerous polyploid species.…”

Section: Hybridisation and Polyploidy In The Mediterranean Regionmentioning

confidence: 91%

How much do we know about the frequency of hybridisation and polyploidy in the Mediterranean region?

et al. 2017

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Natural hybridisation and polyploidy are currently recognised as drivers of biodiversity, despite early scepticism about their importance. The Mediterranean region is a biodiversity hotspot where geological and climatic events have created numerous opportunities for speciation through hybridisation and polyploidy. Still, our knowledge on the frequency of these mechanisms in the region is largely limited, despite both phenomena are frequently cited in studies of Mediterranean plants. We reviewed information available from biodiversity and cytogenetic databases to provide the first estimates of hybridisation and polyploidy frequency in the Mediterranean region. We also inspected the most comprehensive modern Mediterranean Flora (Flora iberica) to survey the frequency and taxonomic distribution of hybrids and polyploids in Iberian Peninsula. We found that <6% of Mediterranean plants were hybrids, although a higher frequency was estimated for the Iberian Peninsula (13%). Hybrids were concentrated in few families and in even fewer genera. The overall frequency of polyploidy (36.5%) was comparable with previous estimates in other regions; however our estimates increased when analysing the Iberian Peninsula (48.8%). A surprisingly high incidence of species harbouring two or more ploidy levels was also observed (21.7%). A review of the available literature also showed that the ecological factors driving emergence and establishment of new entities are still poorly studied in the Mediterranean flora, although geographic barriers seem to play a major role in polyploid complexes. Finally, this study reveals several gaps and limitations in our current knowledge about the frequency of hybridisation and polyploidy in the Mediterranean region. The obtained estimates might change in the future with the increasing number of studies; still, rather than setting the complete reality, we hope that this work triggers future studies on hybridisation and polyploidy in the Mediterranean region.

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“…Alternatively, dysploidy events occur primarily at speciation events, and we therefore surmise that these events correspond to increases in diversification. Descending dysploidy is common throughout the evolutionary history of Compositae (Mota & al., 2016). Most notably, the Eurasian Carduus clade has undergone a dramatic dysploidy reduction from n = 11 to n = 8.…”

Section: ■ Discussionmentioning

confidence: 99%

A prickly puzzle: Generic delimitations in theCarduus‐Cirsiumgroup (Compositae: Cardueae: Carduinae)

Ackerfield

Susanna

Funk

et al. 2020

TAXON

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Generic delimitations within the cosmopolitan Carduus-Cirsium group (i.e., "thistles") have a long history of taxonomic confusion and debate. We present the most comprehensive molecular phylogeny of the group to date to test generic limits, reconstruct the evolution of pappus type, and elucidate the role of chromosomal evolution. We offer two solutions for the recognition of monophyletic genera: (1) consolidate all taxa into one large genus (Carduus or Cirsium), or (2) recognize each major clade as a genus (Carduus, Cirsium, Eriolepis, Notobasis, Picnomon, Silybum, and Tyrimnus). Under the second proposal, the cryptic genus Eriolepis is segregated from Cirsium, and the African Carduus are included within Cirsium. The best diagnosable morphological character to delimit the genera is pollen type, which is not practical in field-based application. We caution that prior to implementing either solution, a thorough, comprehensive morphological analysis of all current members of Cirsium sect. Epitrachys (= genus Eriolepis) be completed. Future morphological studies may find additional achene or leaf surface characters that could be used for practical field identification of the segregate genera. The data show that the plumose pappus state is symplesiomorphic for the group, with one transition to barbellate pappus, likely followed by a reversal to its ancestral state as the group colonized Eurasia. The data are consistent with a North African origin in the region of the Mediterranean and a single colonization event to North America. An ancestral chromosome state of n = 17 is hypothesized for the group, and a descending dysploidy series in Carduus is hypothesized to correspond with the aridification of the Mediterranean region. The Carduus-Cirsium group highlights the difficulty of delimiting morphologically similar, cryptic genera.

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The Evolution of Haploid Chromosome Numbers in the Sunflower Family

Cited by 24 publications

References 67 publications

Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae

Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae

How much do we know about the frequency of hybridisation and polyploidy in the Mediterranean region?

A prickly puzzle: Generic delimitations in theCarduus‐Cirsiumgroup (Compositae: Cardueae: Carduinae)

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