Comparative Analysis of the Chromosomal Positions of rDNA Genes in Species of the &lt;i&gt;tripunctata&lt;/i&gt; Radiation of &lt;i&gt;Drosophila&lt;/i&gt;

Brianti, M.T.; Ananina, Galina; Recco‐Pimentel, Shirlei Maria; Klaczko, Louis Bernard

doi:10.1159/000227840

Cited by 11 publications

(6 citation statements)

References 85 publications

(42 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…number” on ), and there are also examples of 45S rDNA on both X and Y chromosomes in a single karyotype [ 42 , 43 ]. These observations support the hypothesis of the possible ancestral character of sex-linked NORs in insects as proposed in previous studies [ 15 , 29 , 44 , 45 , 46 , 47 ]. It is possible that there is selection towards a preferential position of NOR on sex chromosomes in insects.…”

Section: Resultssupporting

confidence: 92%

Analyses of the Updated “Animal rDNA Loci Database” with an Emphasis on Its New Features

Sochorová

Gálvez

Matyášek

et al. 2021

IJMS

View full text Add to dashboard Cite

We report on a major update to the animal rDNA loci database, which now contains cytogenetic information for 45S and 5S rDNA loci in more than 2600 and 1000 species, respectively. The data analyses show the following: (i) A high variability in 5S and 45S loci numbers, with both showing 50-fold or higher variability. However, karyotypes with an extremely high number of loci were rare, and medians generally converged to two 5S sites and two 45S rDNA sites per diploid genome. No relationship was observed between the number of 5S and 45S loci. (ii) The position of 45S rDNA on sex chromosomes was relatively frequent in some groups, particularly in arthropods (14% of karyotypes). Furthermore, 45S rDNA was almost exclusively located in microchromosomes when these were present (in birds and reptiles). (iii) The proportion of active NORs (positively stained with silver staining methods) progressively decreased with an increasing number of 45S rDNA loci, and karyotypes with more than 12 loci showed, on average, less than 40% of active loci. In conclusion, the updated version of the database provides some new insights into the organization of rRNA genes in chromosomes. We expect that its updated content will be useful for taxonomists, comparative cytogeneticists, and evolutionary biologists.

show abstract

Section: Resultssupporting

confidence: 92%

Analyses of the Updated “Animal rDNA Loci Database” with an Emphasis on Its New Features

Sochorová

Gálvez

Matyášek

et al. 2021

IJMS

View full text Add to dashboard Cite

show abstract

“…The conspicuous absence of the rDNA from the current D. pseudoobscura Y chromosome appears to be derived. Although the location and copy number of the rDNA evolve very rapidly in short periods of time (Lohe and Roberts 2000;Eickbush TH and Eickbush DG 2007), our results in obscura-group species D. guanche coupled with the known locations of the rDNA in other Drosophila species (Hennig et al 1975;Lohe and Roberts 1990;Roy et al 2005;Brianti et al 2009) suggests that the rDNA repeats are ancestrally X and Y linked ( fig. 5 and 6A).…”

Section: Figmentioning

confidence: 69%

Translocation of Y-Linked Genes to the Dot Chromosome in Drosophila pseudoobscura

Larracuente

Noor

Clark

2010

Molecular Biology and Evolution

View full text Add to dashboard Cite

One of the most striking cases of sex chromosome reorganization in Drosophila occurred in the lineage ancestral to Drosophila pseudoobscura, where there was a translocation of Y-linked genes to an autosome. These genes went from being present only in males, never recombining, and having an effective population size of 0.5N to a state of autosomal linkage, where they are passed through both sexes, may recombine, and their effective population size has quadrupled. These genes appear to be functional, and they underwent a drastic reduction in intron size after the translocation. A Y-autosome translocation may pose problems in meiosis if the rDNA locus responsible for X-Y pairing had also moved to an autosome. In this study, we demonstrate that the Y-autosome translocation moved Y-linked genes onto the dot chromosome, a small, mainly heterochromatic autosome with some sex chromosome-like properties. The rDNA repeats occur exclusively on the X chromosome in D. pseudoobscura, but we found that the new Y chromosome of this species harbors four clusters bearing only the intergenic spacer region (IGS) of the rDNA repeats. This arrangement appears analogous to the situation in Drosophila simulans, where X-rDNA to Y-IGS pairing could be responsible for X-Y chromosome pairing. We postulate that the nascent D. pseudoobscura Y chromosome acquired and amplified copies of the IGS, suggesting a potential mechanism for X-Y pairing in D. pseudoobscura.

show abstract

“…No information are available on the chromosomal location of rDNA in B. dorsalis, but the association of genes encoding ribosomal RNA with sex chromosomes has been demonstrated for B. oleae [33] and it seems to be a general feature for tephritids [12,29,34,35] and for some other dipteran groups. This association of rRNA genes with the sex chromosomes may be due to the highly heterochromatic nature of these chromosomes in the Diptera, as rRNA genes are often found in heterochromatic regions [33,36,37]. On this basis we can suppose that the presence of non-LTR retrotransposon R1 on the Y and X chromosomes of B. dorsalis might be associated to the possible presence of the rRNA gene loci on these sex chromosomes.…”

Section: Discussionmentioning

confidence: 97%

Transcribed sex-specific markers on the Y chromosome of the oriental fruit fly, Bactrocera dorsalis

et al. 2020

View full text Add to dashboard Cite

Background The Oriental fruit fly, Bactrocera dorsalis, is a highly polyphagous invasive species with a high reproductive potential. In many tropical and subtropical parts of the world it ranks as one of the major pests of fruits and vegetables. Due to its economic importance, genetic, cytogenetic, genomic and biotechnological approaches have been applied to understand its biology and to implement the Sterile Insect Technique, currently a part of area-wide control programmes against this fly. Its chromosome complement includes five pairs of autosomes and the sex chromosomes. The X and Y sex chromosomes are heteromorphic and the highly heterochromatic and degenerate Y harbours the male factor BdMoY. The characterization of the Y chromosome in this fly apart from elucidating its role as primary sex determination system, it is also of crucial importance to understand its role in male biology. The repetitive nature of the Y chromosome makes it challenging to sequence and characterise. Results Using Representational Difference Analysis, fluorescent in situ hybridisation on mitotic chromosomes and in silico genome resources, we show that the B. dorsalis Y chromosome harbours transcribed sequences of gyf, (typo-gyf) a homologue of the Drosophila melanogaster Gigyf gene, and of a non-LTR retrotransposon R1. Similar sequences are also transcribed on the X chromosome. Paralogues of the Gigyf gene are also present on the Y and X chromosomes of the related species B. tryoni. Another identified Y-specific repetitive sequence linked to BdMoY appears to be specific to B. dorsalis. Conclusions Our random scan of the Y chromosome provides a broad picture of its general composition and represents a starting point for further applicative and evolutionary studies. The identified repetitive sequences can provide a useful Y-marking system for molecular karyotyping of single embryos. Having a robust diagnostic marker associated with BdMoY will facilitate studies on how BdMoY regulates the male sex determination cascade during the embryonic sex-determination window. The Y chromosome, despite its high degeneracy and heterochromatic nature, harbours transcribed sequences of typo-gyf that may maintain their important function in post-transcriptional mRNA regulation. That transcribed paralogous copies of Gigyf are present also on the X and that this genomic distribution is maintained also in B. tryoni raises questions on the evolution of sex chromosomes in Bactrocera and other tephritids.

show abstract

Comparative Analysis of the Chromosomal Positions of rDNA Genes in Species of the <i>tripunctata</i> Radiation of <i>Drosophila</i>

Cited by 11 publications

References 85 publications

Analyses of the Updated “Animal rDNA Loci Database” with an Emphasis on Its New Features

Analyses of the Updated “Animal rDNA Loci Database” with an Emphasis on Its New Features

Translocation of Y-Linked Genes to the Dot Chromosome in Drosophila pseudoobscura

Transcribed sex-specific markers on the Y chromosome of the oriental fruit fly, Bactrocera dorsalis

Contact Info

Product

Resources

About