Project description:Aspergillus flavus is the major producer of carcinogenic aflatoxins in crops worldwide. Natural populations of A. flavus show tremendous variation in aflatoxin production some of which can be attributed to extreme environmental conditions (e.g., drought), differential regulation of the aflatoxin biosynthetic pathway, missing cluster genes or loss-of-function mutations. Understanding the evolutionary processes that generate genetic diversity in A. flavus may also explain quantitative and qualitative differences in aflatoxigenicity. Several population studies provide indirect evidence of recombination in the aflatoxin gene cluster and genome-wide, using multilocus genealogical approaches. More recently A. flavus has been shown to be functionally heterothallic and capable of sexual reproduction in laboratory crosses. In the present study, we characterize the progeny from nine A. flavus crosses and show that crossovers in the aflatoxin cluster coincide with inferred recombination blocks and hotspots in natural populations, which suggests that recombination in the cluster is primarily driven by sex. Moreover, we show that a single crossover event in the cluster can restore aflatoxigenicity, which is significant as mycotoxin production in A. flavus is highly heritable. aCGH was used to corroborate inferences from cluster-based MLSTs and to possibly identify additional crosovers within the cluster.
Project description:Aspergillus flavus is the major producer of carcinogenic aflatoxins in crops worldwide. Natural populations of A. flavus show tremendous variation in aflatoxin production some of which can be attributed to extreme environmental conditions (e.g., drought), differential regulation of the aflatoxin biosynthetic pathway, missing cluster genes or loss-of-function mutations. Understanding the evolutionary processes that generate genetic diversity in A. flavus may also explain quantitative and qualitative differences in aflatoxigenicity. Several population studies provide indirect evidence of recombination in the aflatoxin gene cluster and genome-wide, using multilocus genealogical approaches. More recently A. flavus has been shown to be functionally heterothallic and capable of sexual reproduction in laboratory crosses. In the present study, we characterize the progeny from nine A. flavus crosses and show that crossovers in the aflatoxin cluster coincide with inferred recombination blocks and hotspots in natural populations, which suggests that recombination in the cluster is primarily driven by sex. Moreover, we show that a single crossover event in the cluster can restore aflatoxigenicity, which is significant as mycotoxin production in A. flavus is highly heritable. aCGH was used to corroborate inferences from cluster-based MLSTs and to possibly identify additional crosovers within the cluster. aCGH comparison between 3 strains of A. flavus: 2 parental (P) and 1 progeny (F1) analyzed at the probe level. A total of 9 trio comparisons were made from a total of 18 isolates analyzed by aCGH. Trio comparisons are as follows: IC278 (P), IC1179 (P) and IC1650 (F1); IC201 (P), IC310 (P) and IC1719 (F1); IC307 (P), IC308 (P) and IC1751 (F1); IC277 (P), IC311 (P) and IC1766 (F1); IC277 (P), IC311 (P) and IC1775 (F1); IC244 (P), IC277 (P) and IC2205 (F1); IC244 (P), IC277 (P) and IC2207 (F1); IC301 (P), IC1179 (P) and IC2171 (F1); and finally IC244 (P), IC277 (P) and IC2209 (F1).
Project description:This SuperSeries is composed of the following subset Series: GSE28239: Identification and functional impact of genomic copy number variants in zebrafish, an important human disease model (Zebrafish Strain CNVs) (expression array) GSE28276: Identification and functional impact of genomic copy number variants in zebrafish, an important human disease model (Zebrafish Strain CNVs) (CGH ZV81M) GSE28278: Identification and functional impact of genomic copy number variants in zebrafish, an important human disease model (Zebrafish Strain CNVs) (CGH ZV81M 2) GSE33962: Extensive genetic diversity and substructuring among zebrafish strains revealed through copy number variant analysis (CGH) Refer to individual Series
Project description:Daghestan, with its exceptional combination of linguistic, geographic, and cultural diversity, presents an excellent natural laboratory for tracking the influence of demographic processes on patterns of genetic variation. This study was designed to investigate the co-evolution of genes and languages, comparing and contrasting patterns of linguistic, genetic and geographic variation among Daghestani populations.
Project description:As human populations migrated to diverse geographical regions, they encountered varying pathogens, leading to pronounced natural selection pressures on the immune system. Analysis of nonsynonymous single nucleotide polymorphisms (nsSNPs) across major geographically structured populations showed greater variation in immune-related genes than in non-immune genes, consistent with pathogen-driven selection, whereas cancer-related genes exhibited lower variation, reflecting evolutionary conservation of critical cellular functions. We prioritized nsSNPs in pattern recognition receptor genes based on population diversity and their association with type I interferon activity. Among the top-ranked variants were rs11554776, rs78233829, and rs7380824 in STING1, which demonstrated functional impacts on intrinsic cGAS-STING1-IFN signaling in cancer cells and potential influences on tumor immunity. We further conducted a genome-wide characterization of nsSNPs in immune-related genes across genetic ancestry populations and established a publicly accessible database. Our study suggests that genetic ancestry-related germline variations may influence cancer immunity and treatment, supporting their consideration in personalized medicine.
Project description:There are very few studies exploring the genetic diversity of tick-borne encephalitis complex viruses. Most of the viruses have been sequenced using capillary electrophoresis, however, very few viruses have been analyzed using deep sequencing to look at the genotypes in each virus population. In this study, different viruses and strains belonging to the tick-borne encephalitis complex were sequenced and genetic diversity was analyzed. Shannon entropy and single nucleotide variants were used to compare the viruses. Then genetic diversity was compared to the phylogenetic relationship of the viruses.