Cytologische Untersuchungen an Limnanthes Douglasii R. Br.

Propach, H.

doi:10.1007/bf00587420

Cited by 9 publications

(2 citation statements)

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“…Chromosome numbers have been obtained from 22 species, 21 of which were diploid with 18 chromosomes, and counts of 18, 20 and 36 have been obtained from the widely cultivated N. strumosa (Heitz 1927, Propach 1934, La Cour 1945, Bolkhovskikh et al 1969, Ornduff 1969, Steiner 1996. Previous cytological investigations of Nemesia have been limited to obtaining chromosome numbers, and there have been no detailed investigations of chromosome morphology.…”

Section: Introductionmentioning

confidence: 99%

Ribosomal DNA locus evolution in Nemesia: transposition rather than structural rearrangement as the key mechanism?

2006

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We investigated chromosome evolution in Nemesia using fluorescent in-situ hybridization (FISH) to identify the locations of 5S and 45S (18-26S) ribosomal genes. Although there was conservation between Nemesia species in chromosome number, size and centromere position, there was large variation in both number and position of ribosomal genes in different Nemesia species (21 different arrangements of 45S and 5S rRNA genes were observed in the 29 Nemesia taxa studied). Nemesia species contained between one and three pairs of 5S arrays and between two and four pairs of 45S arrays. These were either sub-terminally or interstitially located and 45S and 5S arrays were often located on the same chromosome pair. Comparison of the positions of rDNA arrays with meiotic chromosome behaviour in interspecific hybrids of Nemesia suggests that some of the changes in the positions of rDNA have not affected the surrounding chromosome regions, indicating that rDNA has changed position by transposition. Chromosome evolution is frequently thought to occur via structural rearrangements such as inversions and translocations. We suggest that, in Nemesia, transposition of rDNA genes may be equally if not more important in chromosome evolution.

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Section: Introductionmentioning

confidence: 99%

Ribosomal DNA locus evolution in Nemesia: transposition rather than structural rearrangement as the key mechanism?

2006

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“…This low chromosome number corresponded to that of Arabidopsis (then known as Stenogramma thalianum; Laibach, 1907), but the chromosomes of Limnanthes were much larger. The small number of large (5-10 lm; Fries, 1936) and morphologically distinct chromosomes attracted the interest of some researchers (e.g., Arroyo, 1973;Fries, 1936;Propach, 1934), but the meadowfoam species never established themselves as important research models.…”

Section: Introductionmentioning

confidence: 99%

Genomes, repeatomes and interphase chromosome organization in the meadowfoam family (Limnanthaceae, Brassicales)

et al. 2022

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SUMMARY The meadowfoam family (Limnanthaceae) is one of the smallest and genomically underexplored families of the Brassicales. The Limnanthaceae harbor about seven species in the genus Limnanthes (meadowfoam) and Floerkea proserpinacoides (false mermaidweed), all native to North America. Because all Limnanthes and Floerkea species have only five chromosome pairs, i.e., a chromosome number rare in Brassicales and shared with Arabidopsis thaliana (Arabidopsis), we examined the Limnanthaceae genomes as a potential model system. Using low‐coverage whole‐genome sequencing data, we reexamined phylogenetic relationships and characterized the repeatomes of Limnanthaceae genomes. Phylogenies based on complete chloroplast and 35S rDNA sequences corroborated the sister relationship between Floerkea and Limnanthes and two major clades in the latter genus. The genome size of Limnanthaceae species ranges from 1.5 to 2.1 Gb, apparently due to the large increase in DNA repeats, which constitute 60–70% of their genomes. Repeatomes are dominated by long terminal repeat retrotransposons, while tandem repeats represent only less than 0.5% of the genomes. The average chromosome size in Limnanthaceae species (340–420 Mb) is more than 10 times larger than in Arabidopsis (32 Mb). A three‐dimensional fluorescence in situ hybridization analysis demonstrated that the five chromosome pairs in interphase nuclei of Limnanthes species adopt the Rabl‐like configuration.

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Class Magnoliopsida (Dicotyledons)

2009

Flowering Plants

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Cytologische Untersuchungen an Limnanthes Douglasii R. Br.

Cited by 9 publications

References 10 publications

Ribosomal DNA locus evolution in Nemesia: transposition rather than structural rearrangement as the key mechanism?

Ribosomal DNA locus evolution in Nemesia: transposition rather than structural rearrangement as the key mechanism?

Genomes, repeatomes and interphase chromosome organization in the meadowfoam family (Limnanthaceae, Brassicales)

Class Magnoliopsida (Dicotyledons)

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