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Edward Strobel

Bio: Edward Strobel is an academic researcher from Harvard University. The author has contributed to research in topics: Genome & Transposable element. The author has an hindex of 2, co-authored 4 publications receiving 289 citations.

Papers
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Journal ArticleDOI
01 Jun 1979-Cell
TL;DR: The results indicate that 412, copia and 297 are capable of evolutionarily rapid transpositions to new chromosomal sites and are able to be passed on from D. melanogaster strains to individuals from the same laboratory stock.

204 citations


Cited by
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Journal ArticleDOI
TL;DR: It is argued that this variation in plant cell culture itself generates genetic variability (somaclonal variation) that may be employed to enhance the exchange required in sexual hybrids for the introgression of desirable alien genes into a crop species.
Abstract: It is concluded from a review of the literature that plant cell culture itself generates genetic variability (somaclonal variation). Extensive examples are discussed of such variation in culture subclones and in regenerated plants (somaclones). A number of possible mechanisms for the origin of this phenomenon are considered. It is argued that this variation already is proving to be of significance for plant improvement. In particular the phenomenon may be employed to enhance the exchange required in sexual hybrids for the introgression of desirable alien genes into a crop species. It may also be used to generate variants of a commercial cultivar in high frequency without hybridizing to other genotypes.

3,113 citations

Journal ArticleDOI
17 Apr 1980-Nature
TL;DR: Natural selection operating within genomes will inevitably result in the appearance of DNAs with no phenotypic expression whose only ‘function’ is survival within genomes.
Abstract: Natural selection operating within genomes will inevitably result in the appearance of DNAs with no phenotypic expression whose only ‘function’ is survival within genomes. Prokaryotic transposable elements and eukaryotic middle-repetitive sequences can be seen as such DNAs, and thus no phenotypic or evolutionary function need be assigned to them.

1,694 citations

Journal ArticleDOI
TL;DR: This analysis represents an initial characterization of the transposable elements in the Release 3 euchromatic genomic sequence of D. melanogaster for which comparison to the transPOSable elements of other organisms can begin to be made.
Abstract: Transposable elements are found in the genomes of nearly all eukaryotes. The recent completion of the Release 3 euchromatic genomic sequence of Drosophila melanogaster by the Berkeley Drosophila Genome Project has provided precise sequence for the repetitive elements in the Drosophila euchromatin. We have used this genomic sequence to describe the euchromatic transposable elements in the sequenced strain of this species. We identified 85 known and eight novel families of transposable element varying in copy number from one to 146. A total of 1,572 full and partial transposable elements were identified, comprising 3.86% of the sequence. More than two-thirds of the transposable elements are partial. The density of transposable elements increases an average of 4.7 times in the centromere-proximal regions of each of the major chromosome arms. We found that transposable elements are preferentially found outside genes; only 436 of 1,572 transposable elements are contained within the 61.4 Mb of sequence that is annotated as being transcribed. A large proportion of transposable elements is found nested within other elements of the same or different classes. Lastly, an analysis of structural variation from different families reveals distinct patterns of deletion for elements belonging to different classes. This analysis represents an initial characterization of the transposable elements in the Release 3 euchromatic genomic sequence of D. melanogaster for which comparison to the transposable elements of other organisms can begin to be made. These data have been made available on the Berkeley Drosophila Genome Project website for future analyses.

593 citations

Journal ArticleDOI
TL;DR: Analytical and simulation models of the population dynamics of transposable elements in randomly mating populations, derived on the assumption of independence between different loci, and compared with simulation results show the general pattern seen in the simulations agrees quite well with theory.
Abstract: This paper describes analytical and simulation models of the population dynamics of transposable elements in randomly mating populations. The models assume a finite number of chromosomal sites that are occupable by members of a given family of elements. Element frequencies can change as a result of replicative transposition, loss of elements from occupied sites, selection on copy number per individual, and genetic drift. It is shown that, in an infinite population, an equilibrium can be set up such that not all sites in all individuals are occupied, allowing variation between individuals in both copy number and identity of occupied sites, as has been observed for several element families in Drosophila melanogaster. Such an equilibrium requires either regulation of transposition rate in response to copy number per genome, a sufficiently strongly downwardly curved dependence of individual fitness on copy number, or both. The probability distributions of element frequencies, generated by the effects of finite population size, are derived on the assumption of independence between different loci, and compared with simulation results. Despite some discrepancies due to violation of the independence assumption, the general pattern seen in the simulations agrees quite well with theory.Data from Drosophila population studies are compared with the theoretical models, and methods of estimating the relevant parameters are discussed.

411 citations

Journal ArticleDOI
01 Sep 1981-Cell
TL;DR: A simple, rapid method for retrieving cloned segments carrying a copy of the transposable element together with contiguous sequences corresponding to this allele and its application to the cloning of the DNA sequences of other genes in Drosophila is discussed.

407 citations