ABSTRACT: Analysis of SNP variation in candidate genes to identify genes associated with adaptation to exposure to wastewater treatment work effluents.
Project description:Many biomonitoring tools/approaches have been proposed to assess presence of endocrine active chemicals (EACs) and their biological effects in the field. Although these tools have provided valuable information, they are often limited by their specificity for certain groups of EACs and they may not account for interactions between EACs. This study aims to evaluate utility of transcriptomic and metabolomic technologies for effects monitoring in the field, and to advance integration of omic and environmental chemistry data sets. The objective was to utilize transcriptomic biomonitoring to determine the relative contribution of wastewater treatment plant effluents to biological effects observed in fish exposed to ambient waters receiving the effluents.
Project description:<p>Due to a unique adaptation to high altitude, the Tibetan Plateau population has been the subject of much research interest. In this study, we conducted whole genome sequencing of 27 Tibetan individuals. Through our analysis, we inferred a detailed history of demography and revealed the natural selection of Tibetan population. We provided evidence of genetic separation between the two subpopulations of Han and Tibetans as early as 44 to 58 thousand years ago, replicated previously reported high altitude adaptation genes, including <i>EPAS1</i> and <i>EGLN1</i>, and reported three new candidate genes, including <i>PTGIS</i>, <i>VDR</i>, and <i>KCTD12</i>.</p>
Project description:Purpose: The goal of the current study was to find the candidate genes responsible for the habita specific clock variation in N. discreta. Methods: We performed RNA-seq experiment using four strains ; African parent (FGSC8831), North American parent (FGSC 8578) and two representative progeny representing African clock phenotype (N309-89) and North American clock phenotype (N309-50). Results: We identified one candidate gene that meets our criteria; confirmed it's expression by qPCR and it's expression pattern is associated with parent genotype. Conclusions: Our approach using the expression profiles and SNP data of two parents and two representative progeny led us to identify a candidate gene for a complex clock adaptation phenotype.
Project description:Affymetrix single nucleotide polymorphism (SNP) array data were used to study genes that underlie human adaptation to climatic stress, with a focus on genetic changes that lead to long-term cold tolerance. Siberia provides the best opportunity to investigate the genetic mechanisms of cold resistance because of the long-term ancestry of indigenous populations in some of the coldest climates on earth. While much of northern Europe was under ice throughout the last glacial period, Siberia remained relatively ice free, and archaeological evidence suggests that people inhabited this region for more than 40,000 years. We gathered SNP data from ~200 individuals from 15 indigenous Siberian populations that inhabit a range of arctic climates and compare their patterns of genetic variation with those from other world populations from warmer climates.Particular attention is paid to regions containing genes that have been previously implicated in cold adaptation or that function in known pathways connected to energy metabolism or cold adapted phenotypes (e.g., those involved in basal metabolic rate and brown adipose tissue function).
Project description:Bacterial adaptation involves extensive cellular reorganization. In particular, growth rate adjustments are associated with substantial modifications of gene expression and mRNA abundance. In this work we aimed to assess the role of mRNA degradation during such variations. A genome-wide transcriptomic-based method was used to determine mRNA half-lives. The model bacterium Lactococcus lactis was used and five growth rates were studied in continuous cultures under isoleucine-limitation and in batch cultures during the adaptation to the isoleucine starvation. During continuous isoleucine-limited growth, the mRNAs of different genes had different half-lives. The stability of most of the transcripts was not constant, and increased as the growth rate decreased. This half-life diversity was analyzed to investigate determinants of mRNA stability. The concentration, length, codon adaptation index and secondary structures of mRNAs were found to contribute to the regulation of mRNA stability in these conditions. However, the growth rate was, by far, the most influential determinant. The respective influences of mRNA degradation and transcription on the regulation of intra-cellular transcript concentration were estimated. The role of degradation on mRNA homeostasis was clearly evidenced: for more than 90 % of the mRNAs studied during continuous isoleucine-limited growth of L. lactis, degradation was antagonistic to transcription. Although both transcription and degradation had, opposite effects,, the mRNA changes in response to growth rate were driven by transcription. Interestingly, degradation control increased during the dynamic adaptation of bacteria as the growth rate reduced due to progressive isoleucine starvation in batch cultures. This work shows that mRNA decay differs between gene transcripts and according to the growth rate. It demonstrates that mRNA degradation is an important regulatory process involved in bacterial adaptation. However, its impact on the regulation of mRNA levels is smaller than that of transcription in the conditions studied. In the study presented here mRNA stabilities were analyzed at 5 growth rates. For each growth rate mRNA levels were measured in a time course experiment following rifampicin addition. At least 12 time points per growth rate are available, including 3 replicates of the zero.
Project description:Divergent adaptation can be associated with reproductive isolation in the process of speciation. We recently demonstrated the link between divergent adaptation and the onset of reproductive isolation in experimental populations of the yeast Saccharomyces cerevisiae evolved from a single progenitor in either a high-salt or a low-glucose environment. However, the genetic basis for adaptation and reproductive isolation remained unknown in this system. Here, we use whole-genome re-sequencing of representatives of three populations to identify 15 candidate mutations, six of which explained the adaptive increases in mitotic fitness in the two environments. In two populations evolved in high salt, two different mutations occurred in the proton efflux pump gene PMA1 and the global transcriptional repressor gene CYC8; the ENA genes encoding sodium efflux pumps were over-expressed once through expansion of this gene cluster and once as a result of the mutation in the regulator CYC8. In the population from low glucose, one mutation occurred in MDS3, which modulates growth at high pH, and one in MKT1, a global regulator of mRNAs encoding mitochondrial proteins, the latter recapitulating a naturally-occurring variant. A Dobzhansky-Muller (DM) incompatibility between the evolved alleles of PMA1 and MKT1 strongly depressed fitness in the low-glucose environment. This DM interaction is the first reported between experimentally evolved alleles of known genes and shows how reproductive isolation can arise rapidly when divergent selection is strong. Evolved and progenitor strains were grown in stressed and unstressed conditions to identify role of mutations in gene expression.
Project description:SNP array data from 12 childhood adrenocortical tumors (ACT) were used to identify recurrent chromosome rearrangements and candidate driver genes.
Project description:Caloric restriction extends lifespan, an effect once thought to involve attenuation of reactive oxygen species (ROS) generated by aerobic metabolism. However, recent evidence suggests that caloric restriction may in fact raise ROS levels, which in turn provides protection from acute doses of oxidant through a process called adaptation. To shed light on the molecular mechanisms of adaptation, we designed a series of genome-wide deletion fitness screens to identify genes involved in adaptation to hydrogen peroxide.
Project description:Bacterial adaptation involves extensive cellular reorganization. In particular, growth rate adjustments are associated with substantial modifications of gene expression and mRNA abundance. In this work we aimed to assess the role of mRNA degradation during such variations. A genome-wide transcriptomic-based method was used to determine mRNA half-lives. The model bacterium Lactococcus lactis was used and five growth rates were studied in continuous cultures under isoleucine-limitation and in batch cultures during the adaptation to the isoleucine starvation. During continuous isoleucine-limited growth, the mRNAs of different genes had different half-lives. The stability of most of the transcripts was not constant, and increased as the growth rate decreased. This half-life diversity was analyzed to investigate determinants of mRNA stability. The concentration, length, codon adaptation index and secondary structures of mRNAs were found to contribute to the regulation of mRNA stability in these conditions. However, the growth rate was, by far, the most influential determinant. The respective influences of mRNA degradation and transcription on the regulation of intra-cellular transcript concentration were estimated. The role of degradation on mRNA homeostasis was clearly evidenced: for more than 90 % of the mRNAs studied during continuous isoleucine-limited growth of L. lactis, degradation was antagonistic to transcription. Although both transcription and degradation had, opposite effects,, the mRNA changes in response to growth rate were driven by transcription. Interestingly, degradation control increased during the dynamic adaptation of bacteria as the growth rate reduced due to progressive isoleucine starvation in batch cultures. This work shows that mRNA decay differs between gene transcripts and according to the growth rate. It demonstrates that mRNA degradation is an important regulatory process involved in bacterial adaptation. However, its impact on the regulation of mRNA levels is smaller than that of transcription in the conditions studied.