Please use this identifier to cite or link to this item:
Title: Functional repetitive sequences and fragile sites in chromosomes of Lolium perenne L.
Keywords: Fragile sites
45S rDNA
Chromosomal rearrangements
Issue Date: Mar-2015
Publisher: Springer
Citation: ROCHA, L. C. et al. Functional repetitive sequences and fragile sites in chromosomes of Lolium perenne L. Protoplasma, [S.l.], v. 252, n. 2, p. 451-460, Mar. 2015.
Abstract: Lolium perenne is considered a high-quality forage widely used in temperate regions to meet the shortage of forage during the winter. In this species, some peculiarities related to cytogenetic aspects have already been described, as the variability in number and position of 45S ribosomal DNA (rDNA) sites and the expression of fragile sites, which require further studies to support the understanding of their causes and consequences. In this way, this study aimed to evaluate the relationship between the expression of fragile sites and functional repetitive sequences (rDNA and telomeric) in chromosomes of diploid and polyploid cultivars of L. perenne. The techniques of FISH, Ag-NOR and fluorescence banding were used to assess the distribution of sites of 45S rDNA, 5S, telomeric sequences, and the transcriptional activity of the 45S ribosomal genes and the distribution of AT- and/or GC-rich sequences in L. perenne, respectively. There was variability in the number and location of 45S rDNA sites, which was not observed for 5S rDNA sites. One of the genotypes showed two 45S rDNA sites on the same chromosome, located in different chromosome arms. Breaks and gaps were found in 45S rDNA sites in most metaphases evaluated for both cultivars. Telomeric sequences were not detected at the end of the chromosomal fragments corresponding to the location of breaks at 45S sites. Apparently, the transcriptional activity was modified in fragile sites. Variation in the number and size of nucleoli, nucleolar fusions and dissociations were observed. All CMA+ bands were colocalized with the 45S sites.
Appears in Collections:DBI - Artigos publicados em periódicos

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.