Genome evolution in alpine oat-like grasses through homoploid hybridization and polyploidy

Winterfeld, Grit; Wölk, Alexandra; Röser, Martin

doi:10.1093/aobpla/plw039

Cited by 6 publications

(6 citation statements)

References 45 publications

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“…Up to now, none of the hypotheses on the chromosomal evolution of Phalaris species could provide consistent information about the structure of an ancestral karyotype, the mode of basic number reduction, karyotype differentiation and the mode of genome composition in the polyploids. Fluorescence in situ hybridisation technique has been widely applied for the analysis of parental genomes in hybrids and auto/allopolyploids, and also for chromosome evolution in closely related species [ 28 , 29 , 30 ]. Specific repetitive sequences such as the tandemly repeated 5S and 45S rDNA have been used in numerous studies as cytogenetic marker [ 31 , 32 , 33 , 34 ] to compare the cytogenetic positions of 5S and 45S rDNA sites among relative species.…”

Section: Introductionmentioning

confidence: 99%

Karyotype evolution in Phalaris (Poaceae): The role of reductional dysploidy, polyploidy and chromosome alteration in a wide-spread and diverse genus

et al. 2018

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Karyotype characteristics can provide valuable information on genome evolution and speciation, in particular in taxa with varying basic chromosome numbers and ploidy levels. Due to its worldwide distribution, remarkable variability in morphological traits and the fact that ploidy change plays a key role in its evolution, the canary grass genus Phalaris (Poaceae) is an excellent study system to investigate the role of chromosomal changes in species diversification and expansion. Phalaris comprises diploid species with two basic chromosome numbers of x = 6 and 7 as well as polyploids based on x = 7. To identify distinct karyotype structures and to trace chromosome evolution within the genus, we apply fluorescence in situ hybridisation (FISH) of 5S and 45S rDNA probes in four diploid and four tetraploid Phalaris species of both basic numbers. The data agree with a dysploid reduction from x = 7 to x = 6 as the result of reciprocal translocations between three chromosomes of an ancestor with a diploid chromosome complement of 2n = 14. We recognize three different genomes in the genus: (1) the exclusively Mediterranean genome A based on x = 6, (2) the cosmopolitan genome B based on x = 7 and (3) a genome C based on x = 7 and with a distribution in the Mediterranean and the Middle East. Both auto- and allopolyploidy of genomes B and C are suggested for the formation of tetraploids. The chromosomal divergence observed in Phalaris can be explained by the occurrence of dysploidy, the emergence of three different genomes, and the chromosome rearrangements accompanied by karyotype change and polyploidization. Mapping the recognized karyotypes on the existing phylogenetic tree suggests that genomes A and C are restricted to sections Phalaris and Bulbophalaris, respectively, while genome B occurs across all taxa with x = 7.

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Section: Introductionmentioning

confidence: 99%

Karyotype evolution in Phalaris (Poaceae): The role of reductional dysploidy, polyploidy and chromosome alteration in a wide-spread and diverse genus

et al. 2018

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“…It has been widely used for identifying specific chromosome regions, analyzing their composition, spatial location, and dynamic chromatin changes during the cell cycle [13][14][15]. Additionally, it has been widely used in unraveling the physical map, structure, and evolution of the genome and in analyzing the relationship between species [16][17][18][19][20][21].…”

Section: Of 12mentioning

confidence: 99%

Comparative Chromosomal Localization of 45S and 5S rDNA Sites in 76 Purple-Fleshed Sweet Potato Cultivars

Chen

Sun

et al. 2020

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In recent years, the purple-fleshed sweet potato has attracted more attention because of its high nutritional value. The cytogenetics of this crop is relatively unexplored, limiting our knowledge on its genetic diversity. Therefore, we conducted cytogenetic analysis of 76 purple-fleshed sweet potato cultivars to analyze the chromosome structure and distribution of 45S and 5S rDNA. We noted that only 62 cultivars had 90 chromosomes, and the others were aneuploid with 88, 89, 91, or 92 chromosomes. The number of 45S rDNA in the 76 cultivars varied from 16 to 21; these sites showed different signal sizes and intensities and were localized at the chromosomal termini or satellite. The number of 5S rDNA was relatively stable; 74 cultivars showed six sites located at the chromosomal sub-terminal or near the centromere. Only the ‘Quanzishu 96’ and ‘Yuzixiang 10’ showed seven and five 5S rDNA sites, respectively. Additionally, both parent cultivars of ‘Quanzishu 96’ showed 18 45S and six 5S rDNA sites. Overall, our results indicate a moderate diversity in the distribution pattern of rDNAs. Our findings provide comprehensive cytogenetic information for the identification of sweet potato chromosomes, which can be useful for developing a high-quality germplasm resource.

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“…setaceum subsp. setaceum in their area of distributional overlap as established through sequencing of the nuclear single copy gene topoisomerase 6 and cytological investigations [ 24 , 50 ].…”

Section: Discussionmentioning

confidence: 99%

Glacial refugia and speciation in a group of wind-pollinated and -dispersed, endemic Alpine species of Helictotrichon (Poaceae)

et al. 2018

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In the Alps phylogeographic studies indicate for small insect-pollinated herbs that climatic fluctuations caused significant population migrations and fragmentations into glacial refugia at the periphery of the Alps. Here we investigate whether this holds also for wind-pollinated and -dispersed species. We therefore analysed the phylogeographic pattern (nuclear and chloroplast dataset) of a clade of the four species of the Helictotrichon parlatorei species group (Poaceae) endemic to the Alps. In contrast to earlier findings for small insect-pollinated herbs no clear barriers to gene flow could be detected in this species group. Instead a few haplotypes are widespread across the entire Alpine region. While the complete absence of a phylogeographic structure in the plastid dataset hints towards very efficient long distance seed dispersal, the moderate phylogeographic structure in the nuclear dataset indicates at least some spatial restriction to pollen dispersal. Rare haplotypes cluster solely in the Western and Southern central Alps and thereby suggest this to be the area of origin for the H. parlatorei species group from where expansion occurred following the presence of calcareous bedrock into the Eastern Alps. We thus conclude that the inclusion of taxa with complementary life-history traits is vital in understanding the glacial history of the Alpine flora.

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Genome evolution in alpine oat-like grasses through homoploid hybridization and polyploidy

Cited by 6 publications

References 45 publications

Karyotype evolution in Phalaris (Poaceae): The role of reductional dysploidy, polyploidy and chromosome alteration in a wide-spread and diverse genus

Karyotype evolution in Phalaris (Poaceae): The role of reductional dysploidy, polyploidy and chromosome alteration in a wide-spread and diverse genus

Comparative Chromosomal Localization of 45S and 5S rDNA Sites in 76 Purple-Fleshed Sweet Potato Cultivars

Glacial refugia and speciation in a group of wind-pollinated and -dispersed, endemic Alpine species of Helictotrichon (Poaceae)

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