scholarly journals Characterization of systemic genomic instability in budding yeast

2020 ◽  
Vol 117 (45) ◽  
pp. 28221-28231 ◽  
Author(s):  
Nadia M. V. Sampaio ◽  
V. P. Ajith ◽  
Ruth A. Watson ◽  
Lydia R. Heasley ◽  
Parijat Chakraborty ◽  
...  
Keyword(s):  
Genomic Instability ◽  
Time Window ◽  
Genomic Variation ◽  
Genomic Disorder ◽  
Whole Genome Analysis ◽  
Entire Genome ◽  
Structural Genomic ◽  
Genome Wide ◽  
Conventional Models

Conventional models of genome evolution are centered around the principle that mutations form independently of each other and build up slowly over time. We characterized the occurrence of bursts of genome-wide loss-of-heterozygosity (LOH) inSaccharomyces cerevisiae, providing support for an additional nonindependent and faster mode of mutation accumulation. We initially characterized a yeast clone isolated for carrying an LOH event at a specific chromosome site, and surprisingly found that it also carried multiple unselected rearrangements elsewhere in its genome. Whole-genome analysis of over 100 additional clones selected for carrying primary LOH tracts revealed that they too contained unselected structural alterations more often than control clones obtained without any selection. We also measured the rates of coincident LOH at two different chromosomes and found that double LOH formed at rates 14- to 150-fold higher than expected if the two underlying single LOH events occurred independently of each other. These results were consistent across different strain backgrounds and in mutants incapable of entering meiosis. Our results indicate that a subset of mitotic cells within a population can experience discrete episodes of systemic genomic instability, when the entire genome becomes vulnerable and multiple chromosomal alterations can form over a narrow time window. They are reminiscent of early reports from the classic yeast genetics literature, as well as recent studies in humans, both in cancer and genomic disorder contexts. The experimental model we describe provides a system to further dissect the fundamental biological processes responsible for punctuated bursts of structural genomic variation.

scholarly journals Characterization of systemic genomic instability in budding yeast

2020 ◽  
Author(s):  
Nadia M. V. Sampaio ◽  
V. P. Ajith ◽  
Ruth A. Watson ◽  
Lydia R. Heasley ◽  
Parijat Chakraborty ◽  
...  
Keyword(s):  
Experimental Model ◽  
Genomic Instability ◽  
Loss Of Heterozygosity ◽  
Time Window ◽  
Budding Yeast ◽  
Mutation Accumulation ◽  
Genomic Variation ◽  
Biological Processes ◽  
Whole Genome Analysis ◽  
Structural Genomic

ABSTRACTConventional models of genome evolution are centered around the principle that mutations form independently of each other and build up slowly over time. We characterized the occurrence of bursts of genome-wide loss-of-heterozygosity (LOH) in Saccharomyces cerevisiae, providing support for an additional non-independent and faster mode of mutation accumulation. We initially characterized a yeast clone isolated for carrying an LOH event at a specific chromosome site, and surprisingly, found that it also carried multiple unselected rearrangements elsewhere in its genome. Whole genome analysis of over 100 additional clones selected for carrying primary LOH tracts revealed that they too contained unselected structural alterations more often than control clones obtained without any selection. We also measured the rates of coincident LOH at two different chromosomes and found that double LOH formed at rates 14-150 fold higher than expected if the two underlying single LOH events occurred independently of each other. These results were consistent across different strain backgrounds, and in mutants incapable of entering meiosis. Our results indicate that a subset of mitotic cells within a population can experience discrete episodes of systemic genomic instability, when the entire genome becomes vulnerable and multiple chromosomal alterations can form over a narrow time window. They are reminiscent of early reports from the classic yeast genetics literature, as well as recent studies in humans, both in the cancer and genomic disorder contexts. The experimental model we describe provides a system to further dissect the fundamental biological processes responsible for punctuated bursts of structural genomic variation.SIGNIFICANCE STATEMENTMutations are generally thought to accumulate independently and gradually over many generations. Here, we combined complementary experimental approaches in budding yeast to track the appearance of chromosomal changes resulting in loss-of-heterozygosity (LOH). In contrast to the prevailing model, our results provide evidence for the existence of a path for non-independent accumulation of multiple chromosomal alteration events over few generations. These results are analogous to recent reports of bursts of genomic instability in human cells. The experimental model we describe provides a system to further dissect the fundamental biological processes underlying such punctuated bursts of mutation accumulation.

scholarly journals Mitotic systemic genomic instability in yeast

2017 ◽  
Author(s):  
Nadia M. V. Sampaio ◽  
Aline Rodrigues-Prause ◽  
V. P. Ajith ◽  
Theodore M. Gurol ◽  
Mary J. Chapman ◽  
...  
Keyword(s):  
Genomic Instability ◽  
Loss Of Heterozygosity ◽  
Chromosomal Instability ◽  
Experimental Approach ◽  
Human Cancer ◽  
Chromosomal Rearrangements ◽  
Point Mutations ◽  
Genomic Variation ◽  
Genomic Disorder ◽  
Structural Genomic

ABSTRACTConventional models of genome evolution generally include the assumption that mutations accumulate gradually and independently over time. We characterized the occurrence of sudden spikes in the accumulation of genome-wide loss-of-heterozygosity (LOH) inSaccharomyces cerevisiae, suggesting the existence of a mitotic systemic genomic instability process (mitSGI). We characterized the emergence of a rough colony morphology phenotype resulting from an LOH event spanning a specific locus (ACE2/ace2-A7). Surprisingly, half of the clones analyzed also carried unselected secondary LOH tracts elsewhere in their genomes. The number of secondary LOH tracts detected was 20-fold higher than expected assuming independence between mutational events. Secondary LOH tracts were not detected in control clones without a primary selected LOH event. We then measured the rates of single and double LOH at different chromosome pairs and found that coincident LOH accumulated at rates 30-100 fold higher than expected if the two underlying single LOH events occurred independently. These results were consistent between two different strain backgrounds, and in mutant strains incapable of entering meiosis. Our results indicate that a subset of mitotic cells within a population experience systemic genomic instability episodes, resulting in multiple chromosomal rearrangements over one or few generations. They are reminiscent of early reports from the classic yeast genetics literature, as well as recent studies in humans, both in the cancer and genomic disorder contexts, all of which challenge the idea of gradual accumulation of structural genomic variation. Our experimental approach provides a model to further dissect the fundamental mechanisms responsible for mitSGI.SIGNIFICANCE STATEMENTPoint mutations and alterations in chromosome structure are generally thought to accumulate gradually and independently over many generations. Here, we combined complementary genetic approaches in budding yeast to track the appearance of chromosomal changes resulting in loss-of-heterozygosity (LOH). Contrary to expectations, our results provided evidence for the occurrence of non-independent accumulation of multiple LOH events over one or a few cell generations. These results are analogous to recent reports of bursts of chromosomal instability in humans. Our experimental approach provides a framework to further dissect the fundamental mechanisms underlying systemic chromosomal instability processes, including in the human cancer and genomic disorder contexts.

scholarly journals Genomic characterization of a pathogenic isolate of Saccharomyces cerevisiae reveals an extensive and dynamic landscape of structural variation

2021 ◽  
Author(s):  
Lydia R. Heasley ◽  
Juan Lucas Argueso
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Structural Variation ◽  
Genome Structure ◽  
Genomic Variation ◽  
Whole Genome Sequencing Data ◽  
Structural Genomic ◽  
Pathogenic Isolate ◽  
A Genome ◽  
Long Read

The budding yeast Saccharomyces cerevisiae has been extensively characterized for many decades and is a critical resource for the study of numerous facets of eukaryotic biology. Recently, the analysis of whole genome sequencing data from over 1000 natural isolates of S. cerevisiae has provided critical insights into the evolutionary landscape of this species by revealing a population structure comprised of numerous genomically diverse lineages. These survey-level analyses have been largely devoid of structural genomic information, mainly because short read sequencing is not suitable for detailed characterization of genomic architecture. Consequently, we still lack a complete perspective of the genomic variation the exists within the species. Single molecule long read sequencing technologies, such as Oxford Nanopore and PacBio, provide sequencing-based approaches with which to rigorously define the structure of a genome, and have empowered yeast geneticists to explore this poorly described realm of eukaryotic genomics. Here, we present the comprehensive genomic structural analysis of a pathogenic isolate of S. cerevisiae, YJM311. We used long read sequence analysis to construct a haplotype-phased, telomere-to-telomere length assembly of the YJM311 diploid genome and characterized the structural variations (SVs) therein. We discovered that the genome of YJM311 contains significant intragenomic structural variation, some of which imparts notable consequences to the genomic stability and developmental biology of the strain. Collectively, we outline a new methodology for creating accurate haplotype-phased genome assemblies and highlight how such genomic analyses can define the structural architectures of S. cerevisiae isolates. It is our hope that through continued structural characterization of S. cerevisiae genomes, such as we have reported here for YJM311, we will comprehensively advance our understanding of eukaryotic genome structure-function relationships, structural diversity, and evolution.

scholarly journals Genome-wide SNP assay reveals structural genomic variation, extended homozygosity and cell-line induced alterations in normal individuals

2006 ◽  
Vol 16 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Javier Simon-Sanchez ◽  
Sonja Scholz ◽  
Hon-Chung Fung ◽  
Mar Matarin ◽  
Dena Hernandez ◽  
...  
Keyword(s):  
Cell Line ◽  
Genomic Variation ◽  
Structural Genomic ◽  
Genome Wide ◽  
Normal Individuals ◽  
Extended Homozygosity

Genomic characterization of a wild diploid isolate of Saccharomyces cerevisiae reveals an extensive and dynamic landscape of structural variation

Genetics ◽  
2021 ◽  
Author(s):  
Lydia R Heasley ◽  
Juan Lucas Argueso
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sequence Analysis ◽  
Structural Variation ◽  
Genome Structure ◽  
Genomic Variation ◽  
Genomic Diversity ◽  
Structural Genomic ◽  
A Genome ◽  
Long Read

Abstract The budding yeast Saccharomyces cerevisiae has been extensively characterized for many decades and is a critical resource for the study of numerous facets of eukaryotic biology. Recently, whole genome sequence analysis of over 1000 natural isolates of S. cerevisiae has provided critical insights into the evolutionary landscape of this species by revealing a population structure comprised of numerous genomically diverse lineages. These survey-level analyses have been largely devoid of structural genomic information, mainly because short read sequencing is not suitable for detailed characterization of genomic architecture. Consequently, we still lack a complete perspective of the genomic variation the exists within the species. Single molecule long read sequencing technologies, such as Oxford Nanopore and PacBio, provide sequencing-based approaches with which to rigorously define the structure of a genome, and have empowered yeast geneticists to explore this poorly described realm of eukaryotic genomics. Here, we present the comprehensive genomic structural analysis of a wild diploid isolate of S. cerevisiae, YJM311. We used long read sequence analysis to construct a haplotype-phased, telomere-to-telomere length assembly of the YJM311 genome and characterized the structural variations (SVs) therein. We discovered that the genome of YJM311 contains significant intragenomic structural variation, some of which imparts notable consequences to the genomic stability and developmental biology of the strain. Collectively, we outline a new methodology for creating accurate haplotype-phased genome assemblies and highlight how such genomic analyses can define the structural architectures of S. cerevisiae isolates. It is our hope that continued structural characterization of S. cerevisiae genomes, such as we have reported here for YJM311, will comprehensively advance our understanding of eukaryotic genome structure-function relationships, structural genomic diversity, and evolution.

scholarly journals Confluence of genes, environment, development, and behavior in a post Genome-Wide Association Study world

2012 ◽  
Vol 24 (4) ◽  
pp. 1195-1214 ◽  
Author(s):  
Scott I. Vrieze ◽  
William G. Iacono ◽  
Matt McGue
Keyword(s):  
Candidate Gene ◽  
Genome Wide Association Study ◽  
Association Studies ◽  
Genomic Structure ◽  
Psychological Theory ◽  
Genomic Variation ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Structural Genomic ◽  
Genome Wide

AbstractThis article serves to outline a research paradigm to investigate main effects and interactions of genes, environment, and development on behavior and psychiatric illness. We provide a historical context for candidate gene studies and genome-wide association studies, including benefits, limitations, and expected payoffs. Using substance use and abuse as our driving example, we then turn to the importance of etiological psychological theory in guiding genetic, environmental, and developmental research, as well as the utility of refined phenotypic measures, such as endophenotypes, in the pursuit of etiological understanding and focused tests of genetic and environmental associations. Phenotypic measurement has received considerable attention in the history of psychology and is informed by psychometrics, whereas the environment remains relatively poorly measured and is often confounded with genetic effects (i.e., gene–environment correlation). Genetically informed designs, which are no longer limited to twin and adoption studies thanks to ever-cheaper genotyping, are required to understand environmental influences. Finally, we outline the vast amount of individual difference in structural genomic variation, most of which remains to be leveraged in genetic association tests. Although the genetic data can be massive and burdensome (tens of millions of variants per person), we argue that improved understanding of genomic structure and function will provide investigators with new tools to test specific a priori hypotheses derived from etiological psychological theory, much like current candidate gene research but with less confusion and more payoff than candidate gene research has to date.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

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