Intense proliferation of rDNA sites and heterochromatic bands in two distantly related Cuscuta species (Convolvulaceae) with very large genomes and symmetric karyotypes
| Autor: | Amália Ibiapino, Marcelo Guerra, Saša Stefanović, Mihai Costea, Miguel A. García |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine CMA and DAPI staining karyotype symmetry dodders QH426-470 Plant Genetics 01 natural sciences Genome 03 medical and health sciences Tandem repeat Genetics Molecular Biology Genome size Phylogenetic tree biology Karyotype biology.organism_classification 030104 developmental biology Evolutionary biology rDNA sites genome size Cuscuta Subgenus Ploidy 010606 plant biology & botany |
| Zdroj: | Genetics and Molecular Biology Genetics and Molecular Biology, Volume: 43, Issue: 3, Article number: e20190068, Published: 15 JUN 2020 Genetics and Molecular Biology v.43 n.3 2020 Sociedade Brasileira de Genética (SBG) instacron:SBG Genetics and Molecular Biology, Vol 43, Iss 3 (2020) |
| ISSN: | 1415-4757 |
| Popis: | The genome size varies widely among angiosperms but only a few clades present huge variation at a low phylogenetic level. Among diploid species of the genus Cuscuta the genome size increased enormously in at least two independent lineages: in species of subgenus Monogynella and in at least one species (C. indecora) of the subgenus Grammica. Curiously, the independent events lead to similar karyotypes, with 2n = 30 mostly metacentric chromosomes. In this paper we compared the patterns of heterochromatic bands and rDNA sites of C. indecora and C. monogyna, aiming to evaluate the role of these repetitive fractions in these karyotypes. We found out that the large genomes of these species were incremented by a huge number of small heterochromatic CMA+ and DAPI+ bands and 5S and 35 rDNA sites, most of them clearly colocalized with CMA+ bands. Silver nitrate impregnation revealed that the maximum number of nucleoli per nucleus was low in both species, suggesting that some of these sites may be inactive. Noteworthy, the tandem repeats did not generate large bands or sites but rather dozens of small blocks dispersed throughout the chromosomes, apparently contributing to conserve the original karyotype symmetry. |
| Databáze: | OpenAIRE |
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