Search results for "5S rDNA"
showing 4 items of 4 documents
Temporal frames of 45S rDNA site-number variation in diploid plant lineages: lessons from the rock rose genus Cistus (Cistaceae)
2016
The perception that the turnover of 45S rDNA site number in plants is highly dynamic pervades the literature on rDNA evolution. However, most reported evidences come from the study of polyploid systems and from crop species subjected to intense agronomic selection. In sharp contrast with polyploids, the evolutionary patterns of rDNA loci number in predominantly diploid lineages have received less attention. Most studies on rDNA loci changes lack explicit temporal frames, and hence their dynamics could not be assessed. Here, we assess the temporal patterns of rDNA site evolution in Cistus, an entirely diploid lineage. We assessed the number and chromosomal position of 45S rDNA loci in Cistus…
Evolutionary site-number changes of ribosomal DNA loci during speciation: complex scenarios of ancestral and more recent polyploid events.
2015
Genes encoding ribosomal RNA are universal key constituents of eukaryotic genomes, but the number of loci varies between species. We assessed the evolutionary trends in site-number changes of rDNA loci during speciation in a lineage of the cabbage family, characterized by complex scenarios of polyploidy. Our results suggest the existence of constrictions to burst loci amplification in the 5S rDNA family in polyploids and an overall trend to further reduce their number. The 45S rDNA site change in polyploids tells a different story, implying loci amplification in most of the polyploid entities.
Chromosomal localization and molecular characterization of three different 5S ribosomal DNA clusters in the sea urchin Paracentrotus lividus
2007
In this paper the chromosomal localization and molecular cloning and characterization of three 5S rDNA clusters of 700 bp (base pairs), 900 bp, and 950 bp in the sea urchin Paracentrotus lividus are reported. Southern blot hybridization demonstrated the existence of three 5S rDNA repeats of differing length in the P. lividus genome. Fluorescence in situ hybridization analysis, performed in parallel on both haploid and diploid metaphases and interphase nuclei using different 5S rDNA units as probes, localized these 5S rDNA clusters in 3 different pairs of P. lividus chromosomes. This is the first complete gene mapping not only in a sea urchin but also in the phylum of echinoderms as a whole…
Data from: Partial sequence homogenization in the 5S multigene families may generate sequence chimeras and spurious results in phylogenetic reconstru…
2013
Multigene families have provided opportunities for evolutionary biologists to assess molecular evolution processes and phylogenetic reconstructions at deep and shallow systematic levels. However, the use of these markers is not free of technical and analytical challenges. Many evolutionary studies that used the nuclear 5S rDNA gene family rarely used contiguous 5S coding sequences due to the routine use of head-to-tail PCR primers that are anchored to the coding region. Moreover, the 5S coding sequences have been concatenated with independent, adjacent gene units in many studies, creating simulated chimeric genes as the raw data for evolutionary analysis. This practice is based on the tacit…