Transposition rates of movable genetic elements in Drosophila melanogaster.

Harada, Ko; Yukuhiro, Kenji; Mukai, Terumi

doi:10.1073/pnas.87.8.3248

Cited by 73 publications

(54 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The heterogeneity of the estimates, at least partially, stems from the activity levels of TEs. Chromosomal aberrations and mobilization of TEs occurred at high frequencies in the MA lines in Mukai and Cockerham (1977) and Voelker et al (1980) (Yamaguchi and Mukai 1974;Harada et al 1990). Indeed, insertional mutations were identified as a major class of mutations in Harada et al (1993)'s MA experiment (Yamaguchi et al 1994; 5 of the 6 mutations analyzed) and the singlegeneration specific locus test by Yang et al (2001; 5 of the 13 mutations).…”

Section: Discussionmentioning

confidence: 97%

Molecular Spectrum of Spontaneous de Novo Mutations in Male and Female Germline Cells of Drosophila melanogaster

et al. 2009

View full text Add to dashboard Cite

We carried out mutation screen experiments to understand the rate and molecular nature of spontaneous de novo mutations in Drosophila melanogaster, which are crucial for many evolutionary issues, but still poorly understood. We screened for eye-color and body-color mutations that occurred in the germline cells of the first generation offspring of wild-caught females. The offspring were from matings that had occurred in the field and therefore had a genetic composition close to that of flies in natural populations. We employed 1554 F 1 individuals from 374 wild-caught females for the experiments to avoid biased contributions of any particular genotype. From $8.6 million alleles screened, we obtained 10 independent mutants: two point mutations (one for each sex), a single deletion of $6 kb in a male, a single transposable element insertion in a female, five large deletions ranging in size from 40 to 500 kb in females, and a single mutation of unknown nature in a male. The five large deletions were presumably generated by nonallelic homologous recombination (NAHR) between transposable elements at different locations, illustrating the mutagenic nature of recombination. The high occurrence of NAHR that we observed has important consequences for genome evolution through the production of segmental duplications.

show abstract

Section: Discussionmentioning

confidence: 97%

Molecular Spectrum of Spontaneous de Novo Mutations in Male and Female Germline Cells of Drosophila melanogaster

et al. 2009

View full text Add to dashboard Cite

show abstract

“…For instance, direct estimates of transposition in Drosophila, based on in situ hybridization studies in inbred lines, are of the magnitude 10 À3 -10 À4 insertions/element/generation, and in yeast are of magnitude 10 À5 , although unlike the elements investigated here, these estimated rates are for retrotransposons (Harada et al 1990;Curcio and Garfinkel 1991;Nuzhdin and Mackay 1994). Transposition rates approaching or exceeding the magnitude observed in this study have, however, been reported in Drosophila crosses for P elements as well as retrotransposons (Berg and Spradling 1991;Labrador et al 1999).…”

Section: Discussionmentioning

confidence: 99%

Low Impact of Germline Transposition on the Rate of Mildly Deleterious Mutation in Caenorhabditis elegans

Bégin

Schoen

2006

Genetics

View full text Add to dashboard Cite

Little is known about the role of transposable element (TE) insertion in the production of mutations with mild effects on fitness, the class of mutations thought to be central to the evolution of many basic features of natural populations. We propagated mutation-accumulation (MA) lines of two RNAi-deficient strains of Caenorhabditis elegans that exhibit germline transposition. We show here that the impact of TE activity was to raise the level of mildly deleterious mutation by 2-to 8.5-fold, as estimated from fecundity, longevity, and body length measurements, compared to that observed in a parallel MA experiment with a control strain characterized by a lack of germline transposition. Despite this increase, the rate of mildly deleterious mutation was between one and two orders of magnitude lower than the rate of TE accumulation, which was approximately two new insertions per genome per generation. This study suggests that high rates of TE activity do not necessarily translate into high rates of detectable nonlethal mutation.

show abstract

“…The effective population size of D. melanogaster has been estimated to be between 10 6 (Kreitman 1983) and 10 5 (Schug et al 1998). The retrotransposition/transposition rates of TEs vary greatly across families in D. melanogaster, ranging from 0 to 3.94 3 10 À3 per element per generation (Ising and Block 1981;Biemont and Aouar 1987;Biemont et al 1990;Harada et al 1990;Nuzhdin andMackay 1994, 1995;Suh et al 1995;Maside et al 2000Maside et al , 2001. (Rates estimated from previous studies are summarized in Supplemental Table S1.)…”

Section: Forward Simulations Of the Population Genetics Of Pirts And mentioning

confidence: 99%

“…(Rates estimated from previous studies are summarized in Supplemental Table S1.) The retrotransposition/transposition rate estimates for individual TE families often differ among studies, but the genomic average retrotransposition/transposition rate is usually within the range of 1.15 3 10 À4 to 3.5 3 10 À4 per element per generation (summarized in Supplemental Table S2), with the excision rate one or two orders of magnitude lower (Eggleston et al 1988;Harada et al 1990;Nuzhdin and Mackay 1995;Nuzhdin et al 1997;Maside et al 2000). In natural populations of D. melanogaster, the selective intensity against a segregating TE has been estimated to be on the order of 10 À5 -10 À4 per element, thus in the quadratic function of fitness, a is usually set at 10 À5 and b is in the range of 10 À6 -10 À5 (Charlesworth et al 1994;Charlesworth 2006, 2008).…”

Section: Forward Simulations Of the Population Genetics Of Pirts And mentioning

confidence: 99%

Population dynamics of PIWI-interacting RNAs (piRNAs) and their targets in Drosophila

Lü¹,

Clark²

2009

Genome Res.

102

View full text Add to dashboard Cite

Transposable elements (TEs) are mobile DNA sequences that make up a large fraction of eukaryotic genomes. Recently it was discovered that PIWI-interacting RNAs (piRNAs), a class of small RNA molecules that are mainly generated from transposable elements, are crucial repressors of active TEs in the germline of fruit flies. By quantifying expression levels of 32 TE families in piRNA pathway mutants relative to wild-type fruit flies, we provide evidence that piRNAs can severely silence the activities of retrotransposons. We incorporate piRNAs into a population genetic framework for retrotransposons and perform forward simulations to model the population dynamics of piRNA loci and their targets. Using parameters optimized for Drosophila melanogaster, our simulation results indicate that (1) piRNAs can significantly reduce the fitness cost of retrotransposons; (2) retrotransposons that generate piRNAs (piRTs) are selectively more advantageous, and such retrotransposon insertions more easily attain high frequency or fixation; (3) retrotransposons that are repressed by piRNAs (targetRTs), however, also have an elevated probability of reaching high frequency or fixation in the population because their deleterious effects are attenuated. By surveying the polymorphisms of piRT and targetRT insertions across nine strains of D. melanogaster, we verified these theoretical predictions with population genomic data. Our theoretical and empirical analysis suggests that piRNAs can significantly increase the fitness of individuals that bear them; however, piRNAs may provide a shelter or Trojan horse for retrotransposons, allowing them to increase in frequency in a population by shielding the host from the deleterious consequences of retrotransposition.[Supplemental material is available online at http://www.genome.org.] Like other kinds of mutations, however, most mutations created by TE insertions are deleterious to the host and are thus selected against. Approximately 50%-80% of mutations arising in D. melanogaster can be attributed to TEs (Finnegan 1992;Ashburner et al. 2004). Based on the copy number of TEs in D. melanogaster, it was estimated that TEs can decrease the fitness of hosts by 0.4%-5% (Eanes et al. 1987;Charlesworth and Langley 1989;Mackay et al. 1992;Pasyukova et al. 2004). The fitness costs of TEs are generally mediated through the following mechanisms: (1) TE insertions disrupt genes (Charlesworth and Charlesworth 1983;Finnegan 1992;McDonald et al. 1997); (2) transcription and translation of TE-encoded genes are costly (Brookfield 1991; Nuzhdin 1999); and (3) ectopic recombination among dispersed and heterozygous TEs creates deleterious chromosomal rearrangements (Montgomery et al. 1987;Langley et al. 1988;Charlesworth and Langley 1989;Petrov et al. 2003). It has been demonstrated that different TE families are regulated by different mechanisms, although these mechanisms are not mutually exclusive (Biemont et al. 1994;Carr et al. 2002;Petrov et al. 2003). Despite their being under strong selective pressure, TEs ...

show abstract

Transposition rates of movable genetic elements in Drosophila melanogaster.

Cited by 73 publications

References 41 publications

Molecular Spectrum of Spontaneous de Novo Mutations in Male and Female Germline Cells of Drosophila melanogaster

Molecular Spectrum of Spontaneous de Novo Mutations in Male and Female Germline Cells of Drosophila melanogaster

Low Impact of Germline Transposition on the Rate of Mildly Deleterious Mutation in Caenorhabditis elegans

Population dynamics of PIWI-interacting RNAs (piRNAs) and their targets in Drosophila

Contact Info

Product

Resources

About