Please use this identifier to cite or link to this item: http://repositorio.ufla.br/jspui/handle/1/34602
metadata.artigo.dc.title: 45S rDNA sites in meiosis of Lolium multiflorum Lam.: variability, non-homologous associations and lack of fragility
metadata.artigo.dc.creator: Rocha, Laiane Corsini
Ferreira, Marco Túlio Mendes
Cunha, Isabela Martinez Fontes
Mittelmann, Andréa
Techio, Vânia Helena
metadata.artigo.dc.subject: Fragile sites
Hemizygosis
Syntheny of rDNA genes
Forage grasses
Chromosome segregation
metadata.artigo.dc.publisher: Springer
metadata.artigo.dc.date.issued: 1-Aug-2018
metadata.artigo.dc.identifier.citation: ROCHA, L. C. et al. 45S rDNA sites in meiosis of Lolium multiflorum Lam.: variability, non-homologous associations and lack of fragility. Protoplasma, [S.l.], v. 256, n. 1, p. 227-235, Jan. 2019. DOI: 10.1007/s00709-018-1292-3.
metadata.artigo.dc.description.abstract: In this study, we evaluated the behavior of 45S ribosomal DNA (rDNA) sites during the meiosis of Lolium multiflorum. The reason to study it in this species is that 45S rDNA sites are usually visualized as gaps in mitotic metaphase chromosomes and were initially denominated fragile sites (FSs). In different species, FSs were related to rearrangements that alter the karyotype and affect the chromosome pairing in meiosis. However, our findings show that the chromosome pairing in L. multiflorum is regular and, as in mitosis, the number of sites is variable. In diakinesis with five sites, one of the bivalents was in hemizygous state while, in diakinesis with seven sites, one of the bivalents had three conspicuous signals, two in syntheny in one of the homologous. Only four cells had gaps in the region of the 45S rDNA. Owing to the lower number of signals observed at the initial stages of meiosis, it is assumed that they are involved both in homologous and non-homologous associations and that they might assist the chromosome pairing. Regarding segregation, only meiocytes with five and six 45S rDNA signals were observed, and they were characterized by the segregation of 2/3 signals in the poles of anaphases I up to metaphases II; 2/2 and 3/3 in anaphases II and telophases II; and also 2/2 and 4/4 in the nuclei of tetrads, unlike the number of 45S signals expected. The numerical non-equivalence of sites among nuclei at later stages of meiosis is explained by the presence of chromosomes with hemizygous sites.
metadata.artigo.dc.identifier.uri: https://link.springer.com/article/10.1007%2Fs00709-018-1292-3
http://repositorio.ufla.br/jspui/handle/1/34602
metadata.artigo.dc.language: en_US
Appears in Collections:DBI - Artigos publicados em periódicos

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