Genomic distribution of transposable elements among individuals of an inbred Drosophila line

Franco, Carmen Di; Galuppi, D.; Junakovic, Nikolaj

doi:10.1007/bf00133706

Cited by 31 publications

(7 citation statements)

References 52 publications

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“…The parameter fi estimated from such frequency data approximates 4N e u, and large differences in estimated values of fi therefore imply real variation in transposition rates of different elements. Direct observations of copia (Lim et al 1983;Eggleston, Johnson-Schlitz & Engels, 1988;Di Franco, Galuppi & Junakovic, 1992) and roo (Eggleston, Johnson-Schlitz & Engels, 1988) transpositions have been reported previously, suggesting these elements in particular transpose relatively frequently. However, we observed no 297 transpositions, but Eggleston, Johnson-Schlitz & Engels (1988) reported a trans-position rate of this element on the X chromosome alone of 2-1 x 10~4, further suggesting there is variation among strains for factors affecting transposition rate.…”

Section: (I) Variable Rates Of Transposition and Excision Among Elemementioning

confidence: 76%

Direct determination of retrotransposon transposition rates inDrosophila melanogaster

Nuzhdin¹,

Mackay²

1994

Genet. Res.

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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.

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Section: (I) Variable Rates Of Transposition and Excision Among Elemementioning

confidence: 76%

Direct determination of retrotransposon transposition rates inDrosophila melanogaster

Nuzhdin¹,

Mackay²

1994

Genet. Res.

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“…The existence of a transposon-based mechanism to generate variability is also suggested from old and recent observations in Drosophila , showing that inbreeding generates both morphological variability (see Lerner 1954 for discussion) and transposon activation (Di Franco et al 1992; Ratner and Vasilyeva 1996). It is well known that the deterioration of populations subjected to inbreeding is a general phenomenon.…”

Section: Environmental Stress and Transposon Activitymentioning

confidence: 83%

“…Many researchers have also observed that inbreeding depression can lead to an increase in phenotypic variability that has been assumed to be of environmental origin. Relevant to this argument, inbreeding has been shown to cause transposon mobilization in Drosophila , again suggesting their involvement in generating phenotypic variability (Di Franco et al 1992). Taken together, these observations suggest that inbreeding is perceived as a stress, triggering the activation of transposons.…”

Section: Environmental Stress and Transposon Activitymentioning

confidence: 98%

Transposons, environmental changes, and heritable induced phenotypic variability

et al. 2014

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The mechanisms of biological evolution have always been, and still are, the subject of intense debate and modeling. One of the main problems is how the genetic variability is produced and maintained in order to make the organisms adaptable to environmental changes and therefore capable of evolving. In recent years, it has been reported that, in flies and plants, mutations in Hsp90 gene are capable to induce, with a low frequency, many different developmental abnormalities depending on the genetic backgrounds. This has suggested that the reduction of Hsp90 amount makes different development pathways more sensitive to hidden genetic variability. This suggestion revitalized a classical debate around the original Waddington hypothesis of canalization and genetic assimilation making Hsp90 the prototype of morphological capacitor. Other data have also suggested a different mechanism that revitalizes another classic debate about the response of genome to physiological and environmental stress put forward by Barbara McClintock. That data demonstrated that Hsp90 is involved in repression of transposon activity by playing a significant role in piwi-interacting RNA (piRNAs)-dependent RNA interference (RNAi) silencing. The important implication is that the fixed phenotypic abnormalities observed in Hsp90 mutants are probably related to de novo induced mutations by transposon activation. In this case, Hsp90 could be considered as a mutator. In the present theoretical paper, we discuss several possible implications about environmental stress, transposon, and evolution offering also a support to the concept of evolvability.

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“…Fixation of different host alleles in laboratory isogenic derivatives might be responsible for the transposition rate variation uncovered between laboratory lines of D. melanogaster (Nuzhdin, 1999). To take an example of one TE family, many laboratory stocks are known to have actively transposing LTR‐containing retrotransposable element copia (Biemont et al ., 1987; Di Franco et al ., 1992; Pasyukova & Nuzhdin, 1993; Charlesworth et al , 1994; Nuzhdin & Mackay, 1994). While we cannot exclude the possibility that these stocks have accumulated new mutations affecting copia transposition rate before copia instability was found, it is more likely that permissive/restrictive alleles segregate in nature.…”

Section: Introductionmentioning

confidence: 99%

Transposable elements in clonal lineages: lethal hangover from sex

Nuzhdin

Petrov

2003

Biological Journal of the Linnean Society

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Long‐term coevolution of transposable elements (TEs) in sexual hosts leads to evolution of extremely active and dangerous mutagens kept in tenuous check by host‐derived mechanisms and via natural selection against TE‐rich genomes. To the extent that sexual reproduction and recombination are important in maintaining a stable TE copy number and a tolerable mutation load, the switch to clonality from sexual reproduction can be extremely damaging and, generally, should lead to clonal lineage extinction. Surprisingly however, the loss of powerful selective mechanisms constraining TEs can be beneficial in the short‐term by immediately eliminating selective load and possibly promoting the early success of clonal lineages. The clonal lineages that do survive in the long‐term must find a way to eliminate or domesticate TEs. Indeed bdelloid rotifers, which are ancient asexuals, do appear to have lost most of the otherwise wide‐spread TEs and might have domesticated others. The path to this TE‐free haven is anything but clear at the moment. We have considered a novel scenario of instantaneous inactivation of TEs by starting off with a genome carrying repressive host alleles for all TEs in the genome. We show that such a scenario appears plausible and provide some limited empirical evidence in its support. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 79, 33–41.

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Genomic distribution of transposable elements among individuals of an inbred Drosophila line

Cited by 31 publications

References 52 publications

Direct determination of retrotransposon transposition rates inDrosophila melanogaster

Direct determination of retrotransposon transposition rates inDrosophila melanogaster

Transposons, environmental changes, and heritable induced phenotypic variability

Transposable elements in clonal lineages: lethal hangover from sex

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