Molecular cytogenetic analyses of haploid and allopolyploid<i>Pellia</i>species

Orzechowska, Maja; Siwinska, Dorota; Małuszyńska, Jolanta

doi:10.1179/037366810x12578498136075

Cited by 18 publications

(17 citation statements)

References 46 publications

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“…In pteridophytes, the rDNA sites have been observed only in four genera ( Osmunda , Ceratopteris , Acrostichum [10] and Selaginella [11]), all of them with terminal or subterminal sites. In bryophytes, data were found only for Marchantia polymorpha [12] and species of Pellia [13], all of them with rDNA sites in terminal position. In a recent paper, a rDNA database containing crude data from a similar sample of plant species has been developed allowing easy access to a large amount of data [14].…”

Section: Introductionmentioning

confidence: 99%

Distribution of 45S rDNA sites in chromosomes of plants: Structural and evolutionary implications

2012

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Background45S rDNA sites are the most widely documented chromosomal regions in eukaryotes. The analysis of the distribution of these sites along the chromosome in several genera has suggested some bias in their distribution. In order to evaluate if these loci are in fact non-randomly distributed and what is the influence of some chromosomal and karyotypic features on the distribution of these sites, a database was built with the position and number of 45S rDNA sites obtained by FISH together with other karyotypic data from 846 plant species.ResultsIn angiosperms the most frequent numbers of sites per diploid karyotype were two and four, suggesting that in spite of the wide dispersion capacity of these sequences the number of rDNA sites tends to be restricted. The sites showed a preferential distribution on the short arms, mainly in the terminal regions. Curiously, these sites were frequently found on the short arms of acrocentric chromosomes where they usually occupy the whole arm. The trend to occupy the terminal region is especially evident in holokinetic chromosomes, where all of them were terminally located. In polyploids there is a trend towards reduction in the number of sites per monoploid complement. In gymnosperms, however, the distribution of rDNA sites varied strongly among the sampled families.ConclusionsThe location of 45S rDNA sites do not vary randomly, occurring preferentially on the short arm and in the terminal region of chromosomes in angiosperms. The meaning of this preferential location is not known, but some hypotheses are considered and the observed trends are discussed.

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Section: Introductionmentioning

confidence: 99%

Distribution of 45S rDNA sites in chromosomes of plants: Structural and evolutionary implications

2012

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“…In bryophytes, cryptic speciation has been increasingly reported (e.g., Heinrichs et al, 2010;Kreier et al, 2010;Orzechowska et al, 2010;Ramaiya et al, 2010) and might offer an explanation for one of the most striking biogeographic features of bryophytes, that is, the extremely low rates of endemism of their floras (see Vanderpoorten et al, 2010a for review). In Macaronesia for example, a biogeographic region comprised of the mid-Atlantic archipelagos of the Azores, Madeira, and the Canary Islands, and which is recognized as an important floristic area for conservation within the European-Mediterranean climate region (Médail and Quezel, 1997), less than 2% of species are endemic to the Canarian archipelago, strongly paling in comparison with the 40% endemism rates observed in angiosperms (Vanderpoorten et al, 2010a).…”

Section: Introductionmentioning

confidence: 99%

Morphology informed by phylogeny reveals unexpected patterns of species differentiation in the aquatic moss Rhynchostegium riparioides s.l.

Hutsemékers

Vieira

Ros

et al. 2012

Molecular Phylogenetics and Evolution

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a b s t r a c tBryophyte floras typically exhibit extremely low levels of endemism. The interpretation, that this might reflect taxonomic shortcomings, is tested here for the Macaronesian flora, using the moss species complex of Rhynchostegium riparioides as a model. The deep polyphyly of R. riparioides across its distribution range reveals active differentiation that better corresponds to geographic than morphological differences. Morphometric analyses are, in fact, blurred by a size gradient that accounts for 80% of the variation observed among gametophytic traits. The lack of endemic diversification observed in R. riparioides in Macaronesia weakens the idea that the low rates of endemism observed in the Macaronesian bryophyte flora might solely be explained by taxonomic shortcomings. To the reverse, the striking polyphyly of North American and European lineages of R. riparioides suggests that the similarity between the floras of these continents has been over-emphasized. Discriminant analyses point to the existence of morphological discontinuities among the lineages resolved by the molecular phylogeny. The global rate of error associated to species identification based on morphology (0.23) indicates, however, that intergradation of shape and size characters among species in the group challenges their identification.

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“…The distribution of 5S rDNA sites was also considered with regard to 45S rDNA sites, aiming to evaluate if the chromosomal linkage of these sites depends only on their abundance in the karyotypes. For bryophytes, information about 5S rDNA was found only for some species of Marchantia and Pellia [Fujisawa et al, 2003;Orzechowska et al, 2010], and for pterydophytes no data were found in the literature. Therefore, these groups were not included in this analysis.…”

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Non-Random Distribution of 5S rDNA Sites and Its Association with 45S rDNA in Plant Chromosomes

Roa¹,

Guerra²

2015

Cytogenet Genome Res

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5S and 45S rDNA sites are the best mapped chromosome regions in eukaryotic chromosomes. In this work, a database was built gathering information about the position and number of 5S rDNA sites in 784 plant species, aiming to identify patterns of distribution along the chromosomes and its correlation with the position of 45S rDNA sites. Data revealed that in most karyotypes (54.5%, including polyploids) two 5S rDNA sites (a single pair) are present, with 58.7% of all sites occurring in the short arm, mainly in the proximal region. In karyotypes of angiosperms with only 1 pair of sites (single sites) they are mostly found in the proximal region (52.0%), whereas in karyotypes with multiple sites the location varies according to the average chromosome size. Karyotypes with multiple sites and small chromosomes (<3 µm) often display proximal sites, while medium-sized (between 3 and 6 µm) and large chromosomes (>6 µm) more commonly show terminal or interstitial sites. In species with holokinetic chromosomes, the modal value of sites per karyotype was also 2, but they were found mainly in a terminal position. Adjacent 5S and 45S rDNA sites were often found in the short arm, reflecting the preferential distribution of both sites in this arm. The high frequency of genera with at least 1 species with adjacent 5S and 45S sites reveals that this association appeared several times during angiosperm evolution, but it has been maintained only rarely as the dominant array in plant genera.

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Molecular cytogenetic analyses of haploid and allopolyploidPelliaspecies

Cited by 18 publications

References 46 publications

Distribution of 45S rDNA sites in chromosomes of plants: Structural and evolutionary implications

Distribution of 45S rDNA sites in chromosomes of plants: Structural and evolutionary implications

Morphology informed by phylogeny reveals unexpected patterns of species differentiation in the aquatic moss Rhynchostegium riparioides s.l.

Non-Random Distribution of 5S rDNA Sites and Its Association with 45S rDNA in Plant Chromosomes

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