scholarly journals DINE-1, the highest copy number repeats in Drosophila melanogaster are non-autonomous endonuclease-encoding rolling-circle transposable elements (Helentrons)

Mobile DNA ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 18 ◽  
Author(s):  
Jainy Thomas ◽  
Komal Vadnagara ◽  
Ellen J Pritham
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Copy Number ◽  
Rolling Circle

scholarly journals The distribution of transposable elements within and between chromosomes in a population of Drosophila melanogaster. I. Element frequencies and distribution

1992 ◽  
Vol 60 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Brian Charlesworth ◽  
Angela Lapid ◽  
Darlene Canada
Keyword(s):  
Population Dynamics ◽  
Drosophila Melanogaster ◽  
Linkage Disequilibrium ◽  
Transposable Elements ◽  
Copy Number ◽  
Polytene Chromosomes ◽  
Chromosome Band ◽  
High Frequencies ◽  
Copy Numbers

SummaryData were collected on the distribution of nine families of transposable elements among second and third chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization of element probes to polytene chromosomes. It was found that the copy numbers per chromosome in the distal sections of the chromosome arms followed a Poisson distribution. Elements appeared to be distributed randomly along the distal sections of the chromosome arms. There was no evidence for linkage disequilibrium in the distal sections of the chromosomes, but some significant disequilibrium was detected in proximal regions. There were many significant correlations between different element families with respect to the identity of the sites that were occupied in the sample. There were also significant correlations between families with respect to sites at which elements achieved relatively high frequencies. Element frequencies per chromosome band were generally low in the distal sections, but were higher proximally. These results are discussed in the light of models of the population dynamics of transposable elements. It is concluded that they provide strong evidence for the operation of a force or forces opposing transpositional increase in copy number. The data suggest that the rate of transposition perelement per generation is of the order of 10−4, for the elements included in this study.

scholarly journals Gene Silencing Triggered by Non-LTR Retrotransposons in the Female Germline ofDrosophila melanogaster

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 521-531 ◽  
Author(s):  
Stéphanie Robin ◽  
Séverine Chambeyron ◽  
Alain Bucheton ◽  
Isabelle Busseau
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Gene Silencing ◽  
Bombyx Mori ◽  
Copy Number ◽  
Transcription Unit ◽  
Ltr Retrotransposons ◽  
Endogenous Gene ◽  
Sequence Identity ◽  
Female Germline

AbstractSeveral studies have recently shown that the activity of some eukaryotic transposable elements is sensitive to the presence of homologous transgenes, suggesting the involvement of homology-dependent genesilencing mechanisms in their regulation. Here we provide data indicating that two non-LTR retrotransposons of Drosophila melanogaster are themselves natural triggers of homology-dependent gene silencing. We show that, in the female germline of D. melanogaster, fragments from the R1 or from the I retrotransposons can mediate silencing of chimeric transcription units into which they are inserted. This silencing is probably mediated by sequence identity with endogenous copies of the retrotransposons because it does not occur with a fragment from the divergent R1 elements of Bombyx mori, and, when a fragment of I is used, it occurs only in females containing functional copies of the I element. This silencing is not accompanied by cosuppression of the endogenous gene homologous to the chimeric transcription unit, which contrasts to some other silencing mechanisms in Drosophila. These observations suggest that in the female germline of D. melanogaster the R1 and I retrotransposons may self-regulate their own activity and their copy number by triggering homology-dependent gene silencing.

scholarly journals A study of ten families of transposable elements on X chromosomes from a population of Drosophila melanogaster

1989 ◽  
Vol 54 (2) ◽  
pp. 113-125 ◽  
Author(s):  
Brian Charlesworth ◽  
Angela Lapid
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Copy Number ◽  
Distal Part ◽  
Polytene Chromosomes ◽  
Chromosome Band ◽  
X Chromosomes ◽  
High Frequencies ◽  
Chromosome Element

SummaryData were collected on the distribution of ten families of transposable elements among fourteen X chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization to polytene chromosomes. It was found that, with the exception of roo, the copy number per chromosome followed a Poisson distribution. There was no evidence for linkage disequilibrium, either within or between families. Some pairs of families of elements were correlated with respect to the identity of the sites that were occupied in the sample, although there was no evidence for a correlation with respect to the sites at which elements attained relatively high frequencies. Elements appeared to be distributed randomly along the distal part of the X chromosome. There was, however, a strong tendency for elements to accumulate at the base of the chromosome. Element frequencies per chromosome band were generally low, except at the base of the chromosome where bands in subdivisions 19E and 20A sometimes had high frequencies of occupation. These results are discussed in the light of models of the population dynamics of transposable elements. It is concluded that they provide strong evidence for the operation of a force or forces opposing transpositional increase in copy number. The accumulation of elements at the base of the chromosome is consistent with the idea that unequal exchange between elements at non-homologous sites is such a force, although other possibilities cannot be excluded at present. The data suggest that the rate of transposition per element per generation is of the order of 10−4, for the elements included in this study.

scholarly journals The distribution of transposable elements on X chromosomes from a natural population of Drosophila simulans

1995 ◽  
Vol 66 (2) ◽  
pp. 159-166 ◽  
Author(s):  
Sergey V. Nuzhdin
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Transposable Element ◽  
Natural Population ◽  
Copy Number ◽  
Polytene Chromosomes ◽  
Distal Region ◽  
Drosophila Simulans ◽  
Chromosome Band ◽  
X Chromosomes

SummaryThe distribution of 13 transposable element families along 15 X chromosomes from an African natural population of Drosophila simulans was determined by in situ hybridization to polytene chromosomes. The transposable elements cloned from Drosophila melanogaster all hybridized with Drosophila simulans chromosomes. The number of copies per family was 3·5 times lower in the latter species and correlated with the copy number per family in Drosophila melanogaster. With the exception of 297, the copy number per chromosome followed a Poisson distribution. Element frequencies per chromosome band were generally low. However, several sites of the distal region and the base of the X chromosome had high frequencies of occupation. Elements had higher abundance at the base of the chromosome compared to distal regions. Overall, the distribution of transposable elements in Drosophila simulans is similar to that found in Drosophila melanogaster. These data provide evidence for the operation of a force (or forces) opposing transpositional increase in copy number, and that this force is weaker at the bases of chromosomes, consistent with the idea that recombination between elements at non-homologous sites contains TE copy number. The reduction in copy number of all TE families in Drosophila simulans compared to Drosophila melanogaster can be explained by stronger selection against transposable element multiplication and/or lower rates of transposition in Drosophila simulans.

scholarly journals Properties of transgenic strains of Drosophila melanogaster containing I transposable elements from Drosophila teissieri

1993 ◽  
Vol 61 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Chantal Vaury ◽  
Alain Pélisson ◽  
Pierre Abad ◽  
Alain Bucheton
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Reverse Transcription ◽  
Copy Number ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
I Factor ◽  
Transgenic Strains ◽  
Drosophila Teissieri

SummaryI factors are transposable elements of Drosophila melanogaster similar to mammalian LINEs, that transpose by reverse transcription of an RNA intermediate and are responsible for the I–R system of hybrid dysgenesis. There are two categories of strains in this species: inducer, that contain about 15 I elements at the various sites on chromosomal arms, and reactive, that lack active I factors. I elements occur in various Drosophila species. Potentially functional I factors from Drosophila teissieri can transpose when introduced by P-element-mediated transformation in a reactive strain of Drosophila melanogaster. We have studied the properties of Drosophila melanogaster strains into which such an I factor from Drosophila teissieri, named Itei, was introduced. Typical hybrid dysgenesis is produced when males carrying Itei are crossed with reactive females. However, more than one copy of the element seems necessary to produce dysgenic traits, whereas only one I factor of Drosophila melanogaster seems to be sufficient. The copy number of Itei in transformed lines maintained by endogamous crosses increases rapidly and stabilizes at values similar to those observed in inducer strains. As Drosophila teissieri contains much fewer copies than the Drosophila melanogaster strains, this suggests that the copy number of I elements is not simply regulated by sequences present in the element itself.

scholarly journals Population dynamics of the copia, mdg1, mdg3, gypsy, and P transposable elements in a natural population of Drosophila melanogaster

1994 ◽  
Vol 63 (3) ◽  
pp. 197-212 ◽  
Author(s):  
C. Biémont ◽  
F. Lemeunier ◽  
M. P. Garcia Guerreiro ◽  
J. F. Brookfield ◽  
C. Gautier ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Natural Population ◽  
Copy Number ◽  
Population Biology ◽  
Insertion Site ◽  
Polytene Chromosomes ◽  
Sharp Decrease ◽  
Theoretical Models ◽  
X Chromosomes

SummaryThe insertion site polymorphism of the copia, mdg1, mdg3, gypsy, and P transposable elements was analysed by in situ hybridization to the polytene chromosomes in genomes of males from a natural population of Drosophila melanogaster. Parameters of various theoretical models of the population biology of transposable elements were estimated from our data, and different hypotheses explaining TE copy number containment were tested. The copia, mdg1 and gypsy elements show evidence for a deficiency of insertions on the X chromosomes, a result consistent with selection against the mutational effects of insertions. On the contrary, mdg3 and P copy numbers fit a neutral model with a balance between regulated transposition and excisions. There is no strong evidence of a systematic accumulation of elements in the distal and proximal regions of the chromosomes where crossing over and ectopic exchanges are reduced. For all chromosome arms but 3L, however, the TE site density increases from the proximal to the distal parts of the chromosomes (the centromeric regions were excluded in this analysis) with sometimes a sharp decrease in density at the extreme tip, following in part the exchange coefficient. The way the copy number of TEs is contained in genomes depends thus on the element considered, and on various forces acting simultaneously, indicating that models of TE dynamics should include details of each element.

scholarly journals Chromosomal Distribution of Transposable Elements in Drosophila melanogaster Test of the Ectopic Recombination Model for Maintenance of Insertion Site Number

Genetics ◽  
1996 ◽  
Vol 144 (1) ◽  
pp. 197-204
Author(s):  
Christine Hoogland ◽  
Christian Biémont
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Dna Content ◽  
Recombination Rate ◽  
Alternative Hypothesis ◽  
Insertion Site ◽  
Polytene Chromosomes ◽  
Negative Relationship ◽  
Site Occupancy ◽  
Site Number

Abstract Data of insertion site localization and site occupancy frequency of P, hobo, I, copia, mdg1, mdg3, 412, 297, and roo transposable elements (TEs) on the polytene chromosomes of Drosophila melanogaster were extracted from the literature. We show that TE insertion site number per chromosomal division was significantly correlated with the amount of DNA. The insertion site number weighted by DNA content was not correlated with recombination rate for all TEs except hobo, for which a positive correlation was detected. No global tendency emerged in the relationship between TE site occupancy frequency, weighted by DNA content, and recombination rate; a strong negative correlation was, however, found for the 3L arm. A possible dominant deleterious effect of chromosomal rearrangements due to recombination between TE insertions is thus not the main factor explaining the dynamics of TEs, since this hypothesis implies a negative relationship between recombination rate and both TE insertion site number and site occupancy frequency. The alternative hypothesis of selection against deleterious effects of insertional mutations is discussed.

scholarly journals Three Groups of Transposable Elements with Contrasting Copy Number Dynamics and Host Responses in the Maize (Zea mays ssp. mays) Genome

PLoS Genetics ◽  
2014 ◽  
Vol 10 (4) ◽  
pp. e1004298 ◽  
Author(s):  
Concepcion M. Diez ◽  
Esteban Meca ◽  
Maud I. Tenaillon ◽  
Brandon S. Gaut
Keyword(s):  
Zea Mays ◽  
Transposable Elements ◽  
Copy Number ◽  
Host Responses ◽  
Number Dynamics

scholarly journals Direct determination of retrotransposon transposition rates in Drosophila melanogaster

1994 ◽  
Vol 63 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Sergey V. Nuzhdin ◽  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Inbred Line ◽  
Copy Number ◽  
Direct Determination ◽  
Hybridization Analysis ◽  
Spontaneous Mutations ◽  
Insertion Sites

SummaryRates of transposition and excision of the Drosophila melanogaster retrotransposon elements mdg3, 297, Doc, roo and copia were estimated directly, by in situ hybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates of Doc, roo and copia were, respectively, 4·2 × 10−5, 3·1 × 10−3 and 1·3 − 10−3; no transpositions of 297 nor mdg3 were observed. Rates of transposition of copia varied significantly among sublines. Excisions were only observed for roo elements, at a rate of 9·0 × 10−6 per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.

Sign in / Sign up

Export Citation Format

Share Document