Author: Randall W. PhillisPublisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 396
Book Description
Evolutionary, Genetic and Molecular Analysis of Transposable Element-induced Mutations in Drosophila Melanogaster
Author: Randall W. PhillisPublisher:
ISBN:
Category : Drosophila melanogaster
Languages : en
Pages : 396
Book Description
Evolution and Impact of Transposable Elements
Author: Pierre CapyPublisher: Springer Science & Business Media
ISBN: 9401148988
Category : Science
Languages : en
Pages : 305
Book Description
During the last 50 years, the perception oftransposable elements (TEs) has changed considerably from selfish DNA to sequences that may contribute significantly to genome function and evolution. The recent increased interest in TEs is based on the realization that they are a major genetic component (at least 10--20%) of all organisms and a major contributor to the mutation process. It is currently estimated that 70--80% of spontaneous mutations are the result of TE-mediated insertions, deletions, or chromosomal rearrangements. Thus, it seems at least plausible that TEs may playa significant role in the adaptation and evolution of natural populations and species. The ubiquity of TEs suggests that they are an old component of genomes which have been vertically transmitted through generations over evolutionary time. However, detailed analyses carried out over the last 20 years have revealed several unusual features of TE evolution: (i) TEs can be horizontally transferred between species; (ii) TE evolutionary rates can be dramatically increased by specific inactivation processes, such as the RIP (Repeat Induced Point mutation) mechanism in fungi; (iii) TEs can influence the regulation of other TEs by insertion or deletion; (iv) different classes of TEs in even distantly related species can be remarkably similar in both structure and function.
Adaptation in Drosophila Melanogaster Natural Populations
Author: Anna Ullastres i CollPublisher:
ISBN:
Category :
Languages : en
Pages : 245
Book Description
"A major challenge of modern Biology is elucidating the genetic basis of adaptation. While there are many SNP-based studies trying to elucidate the genetic basis of genotype-phenotype relationships, the role of transposable element (TE)-induced mutations is understudied. Recent evidences demonstrate that TEs are a powerful tool to identify the genetic basis of adaptive phenotypic traits. Drosophila melanogaster is a good model to study adaptation because it is original from subtropical Africa and only recently colonized out-of-Africa environments. To identify and characterize the role of several candidate TEs in D. melanogaster adaptation, we have followed two different strategies: locus-specific and trait-specific. In the first chapter, we have characterized both at the molecular and phenotypic level FBti0019386, a previously identified candidate adaptive TE. We first elucidated the evolutionary history of this natural insertion and provided evidences of genomic signatures of positive selection. We then explored several phenotypes related to known phenotypic effects of nearby genes, and having plausible connections to fitness variation in nature. We found that flies with FBti0019386 insertion had a shorter developmental time and were more sensitive to stress, which are likely to be the adaptive effect and the cost of selection of this mutation, respectively. Interestingly, these phenotypic effects are not consistent with a role of FBti0019386 in temperate adaptation as has been previously suggested. Indeed, a global analysis of the population frequency of FBti0019386 showed that climatic variables explain well the FBti0019386 frequency patterns only in Australia. These results suggest that further functional validation should be gathered before concluding that a candidate loci is under spatially varying selection. Finally, although FBti0019386 insertion could be inducing the formation of heterochromatin by recruiting HP1a (Heterochromatin Protein 1a) protein, the insertion is associated with up-regulation of sra in adult females. In the second chapter of this thesis, we have studied the impact of several TE insertions in a highly conserved and ecologically relevant trait: the immune response. To do that, we first performed a new genome-wide screening in order to identify a dataset of candidate TEs involved in adaptation. By increasing the number of populations and the number of TEs analyzed compared to similar studies, we were able to increase the number of identified candidate TEs: a total of 121 TEs. Interestingly, we found that genes associated with those TEs are enriched for stress-related functions, specifically we detected a significant enrichment for immune response functions. We combined allele-specific expression (ASE), enhancer assays, and TSS detection experiments to characterize the impact of these TEs in oral immune response to the gram-negative bacteria Pseudomonas entomophila. We were also able to associate the 12 candidate TEs with gene expression changes, and determine some of the molecular mechanisms behind these expression changes. We showed that the allele with the TE was differently expressed in 13 out of the 16 analyzed genes under non-infected and/or infected conditions in at least one of the two genetic backgrounds analyzed. We also show that different TEs alter gene expression by adding promoters and enhancer regulatory sequences to their nearby genes. Although we found evidences pointing to a possible role of TEs in immune response regulation, more experiments should be performed in order to link the identified TEs with a fitness effect in this trait. Overall, our two integrative approaches allowed us to shed light on the role of TEs in generating genomic natural variation potentially underlying adaptation. The results obtained in this work illustrate that TEs are a good tool to bridge the gap between genotypic and phenotypic evolution." -- TDX.
Mechanisms of Life History Evolution
Author: Thomas FlattPublisher: OUP Oxford
ISBN: 0191621021
Category : Science
Languages : en
Pages : 506
Book Description
Life history theory seeks to explain the evolution of the major features of life cycles by analyzing the ecological factors that shape age-specific schedules of growth, reproduction, and survival and by investigating the trade-offs that constrain the evolution of these traits. Although life history theory has made enormous progress in explaining the diversity of life history strategies among species, it traditionally ignores the underlying proximate mechanisms. This novel book argues that many fundamental problems in life history evolution, including the nature of trade-offs, can only be fully resolved if we begin to integrate information on developmental, physiological, and genetic mechanisms into the classical life history framework. Each chapter is written by an established or up-and-coming leader in their respective field; they not only represent the state of the art but also offer fresh perspectives for future research. The text is divided into 7 sections that cover basic concepts (Part 1), the mechanisms that affect different parts of the life cycle (growth, development, and maturation; reproduction; and aging and somatic maintenance) (Parts 2-4), life history plasticity (Part 5), life history integration and trade-offs (Part 6), and concludes with a synthesis chapter written by a prominent leader in the field and an editorial postscript (Part 7).
Genetic and Molecular Analysis of Mutations Derived from an Unstable X Chromosome in Drosophila Melanogaster
Author: Fang-Miin SheenGenome Evolution
Author: Gabriel A. DoverPublisher: Academic Press
ISBN:
Category : Science
Languages : en
Pages : 410
Book Description
Cumulative Subject Index, Volumes 20-39
Author: Publisher: Academic Press
ISBN: 0080568270
Category : Science
Languages : en
Pages : 201
Book Description
Volume 40 of Advances in Genetics brings together a complete listing of subjects covered in Volumes 20-39 of this premier series. In one easy-to-use source, the interested librarian, student, and researcher can find references to specific articles on topics such as tumor suppressor genes, chromosome rearrangements, apoptosis, bax genes, the human genome project, muscular dystrophy, gene therapy, transcription factors, and transgenic mouse models. This cumulative subject index will serve not only as a complete overview of the major topics published in Advances in Genetics, but also as an indicator of the progress made in genetic research over the years.
Mobile DNA
Author: Douglas E. BergPublisher: Amer Society for Microbiology
ISBN: 9781555810054
Category : Medical
Languages : en
Pages : 972
Book Description
Documents the remarkable mobility of DNA in procaryotic and eucaryotic genomes: the ability of various DNA segments to move to new sites, to invert, and to undergo deletion or amplification, generally without the extensive DNA sequence homology needed for classical recombination. Seventy contributors explore the mechanisms of these rearrangements, how they are regulated, their biological consequences, and their potential use as research tools. For students and researchers of molecular genetics. Annotation copyrighted by Book News, Inc., Portland, OR
Mobile Genetic Elements
Author: David J. SherrattPublisher: Oxford University Press, USA
ISBN:
Category : Art
Languages : en
Pages : 208
Book Description
Mobile genetic elements are present in all organisms. They are a major cause of spontaneous genetic change and are now exploited by geneticists as important tools for obtaining mutants, isolating genes, and for studying gene expression. The approach is comparative and the book addresses transposable elements as genetic tools, mechanisms that lead to genetic change, and how novel elements contribute to organism biology and evolution.
Author: Daniel Alan Barbash