Bear genome study
Ontology highlight
ABSTRACT:
REPOSITORIES: ENA
Similar Datasets
Project description:Middle Pleistocene genome calibrates a revised evolutionary history of extinct cave bears
| PRJEB42442 | ENA
Project description:The PFGRC has developed a cost effective alternative to complete genome sequencing in order to study the genetic differences between closely related species and/or strains. The comparative genomics approach combines Gene Discovery (GD) and Comparative Genomic Hybridization (CGH) techniques, resulting in the design and production of species microarrays that represent the diversity of a species beyond just the sequenced reference strain(s) used in the initial microarray design. These species arrays may then be used to interrogate hundreds of closely related strains in order to further unravel their evolutionary relationships. Many infectious agents that cause emerging and re-emerging diseases appear to evolve from non-virulent forms. We still lack a clear understanding about the natural history of various microbial agents that cause human infectious diseases and the events leading to acquisition of their pathogenic potential. There have been seven pandemics of V. cholerae throughout the history of the mankind. To date, the world population is still experiencing the seventh one which started in the early 1960s. From almost 200 recognized V. cholerae serotypes, the majority of these epidemics are associated with primarily O1 serotype. However there is evidence that this species is undergoing some phenotypic changes during the last decades. Such examples include shifts in some metabolic pathways used for biotyping, phage sensitivity profiling and the acquisition of plasmids that carry multiple genes conferring antimicrobial resistance. Furthermore, the recent emergence of a non-O1 serotype (‘Bengal strain’, classified serologically as O139) has prompted the experts to think that perhaps this genotype will be the predominant one in the upcoming (eighth) pandemic. Besides the O1 and O139, the non-O1 and non-O139 V. cholerae stains are occasionally associated with other severe forms of gastrointestinal disease in humans. Interestingly, many of these non-canonical strains lack the genes encoding the typical virulence factors for this species such as the Cholera-toxin (ctx) and toxin co-regulated pilus (tcpA). Therefore it has been hypothesized that this group of non-canonical V. cholerae pathogens consist of several sub-clones that elicit disease via unknown virulence determinants and underlying mechanisms. The flow of genetic information within this group motivated us to identify novel genes for the purpose of creating a "species" DNA microarray to better understand the ancestral relationships among its members. Based on preliminary genotyping (MLST, and CGH using a single-genome-based array), 10 diverse V. cholerae and one V. mimicus were selected for sequencing. Sequence information obtained from this project, and from other publicly available sources, led to the development of a comprehensive species microarray for V. cholerae group members. The availability of the V. cholerae species DNA microarray has allowed us to carry out a collaborative CGH genotyping project to validate this microarray as well as understand the phylogenomic relationships among members of V. cholerae group.
2009-11-25 | GSE19108 | GEO
Project description:Group A Streptococcus (GAS) has a rich evolutionary history of horizontal transfer among its core genes. Yet, despite extensive genetic mixing, GAS strains have discrete ecological phenotypes. To further our understanding of the molecular basis for ecological phenotypes, comparative genomic hybridization of a set of 97 diverse strains to a GAS pan-genome microarray was undertaken, and the association of accessory genes with emm genotypes that define tissue tropisms for infection was determined. Of the 22 non-prophage, accessory gene regions (AGRs) identified, only three AGRs account for all statistically significant linkage disequilibrium among strains having the genotypic biomarkers for throat versus skin infection specialist. Networked evolution and population structure analysis of loci representing each of the AGRs reveals that most strains with the skin specialist and generalist biomarkers form discrete clusters, whereas strains with the throat specialist biomarker are highly diverse. To identify co-inherited and co-selected accessory genes, the strength of genetic associations was determined for all possible pair wise combinations of accessory genes among the 97 GAS strains. Accessory genes showing very strong associations provide the basis for an evolutionary model, which reveals that a major transition between many throat and skin specialist haplotypes correlates with the gain or loss of genes encoding fibronectin-binding proteins. This study employs a novel synthesis of tools to help delineate the major genetic changes associated with key adaptive shifts in an extensively recombined bacterial species.
2011-10-03 | GSE31860 | GEO
Project description:Myanmar locates in the crossroads of South Asia, Southeast Asia, and East Asia, and is known for high culture diversity in different ethnic groups. It is considered to be important for understanding human evolutionary history and genetic diversity in East Eurasia. However, relatively few studies have examined the population structure and demographic history in Myanmar to date. In this study, we analyzed more than 220,000 genome-wide SNPs in 175 new samples of five ethnic groups from Myanmar and compared them with the published data. Our results showed that the Myanmar population is intricately substructured, with the main observed clusters corresponding roughly to western/northern highlanders (Chin, Naga, and Jingpo) and central/southern lowlanders (Bamar and Rakhine). The gene flow inferred from South Asia has a substantial influence (~11%) on the gene pool of central/southern lowlanders rather than western/northern highlanders. The genetic admixture is dated around 650 years ago. These findings suggest that the genome-wide variation in Myanmar was likely shaped by the linguistic, cultural, and historical changes.
2019-12-31 | GSE74100 | GEO
Project description:Evolutionary history of Hemerocallis in Japan and levels of interspecific gene flow
| PRJDB10207 | ENA
Project description:As an ancient jawless vertebrate species, the lamprey offers an important model to probe the evolutionary history of retinal cells. In this study, we generated a cell atlas of the adult sea lamprey retina using single-cell RNA sequencing
2024-03-04 | GSE236005 | GEO
Project description:New genes are those that originated relatively recently and are only present in a subset of species in a phylogeny. Evidence from humans and other species has demonstrated that, despite their young age, new genes can exhibit novel functions that are essential for the survival of an organism. One potential mechanism by which new genes gain essential functions is through the acquisition of many new interactions with pre-existing genes. This hypothesis is consistent with well-established observations that genes with many interaction partners are more likely to have essential functions. However, the accumulation of gene-gene interactions is, on average, a slow evolutionary process. This raises the question of how, in a short evolutionary time, new genes can acquire multiple novel interactions and how this might lead to their essential roles in the survival of an organism. In this study, we characterized the evolutionary history and function of a young duplicated gene that quickly became essential for the survival of Drosophila melanogaster. This young gene (CG7804) duplicated from another essential gene (TBPH) through retrotransposition less than four million years ago (Zhang et al. 2010), and is present in few Drosophila species. We found that unlike its evolutionarily conserved, broadly expressed parental gene, CG7804 has evolved rapidly under positive selection since its birth. Despite its young age, functional analyses show that CG7804 is essential for the survival of D. melanogaster. In particular, its expression is essential at different tissues from its parental gene. RNA-seq and ChIP-seq analysis suggests that CG7804 acquired essential function to survival through gaining new DNA binding targets that influence the expression of a suite of genes with other essential function and large number of protein-protein interaction. Our study is an important step towards deciphering the evolutionary trajectory by which duplicated genes functionally diverge from the parental gene and become essential.
2019-06-01 | GSE100342 | GEO
Project description:Although the majority of previous work on campylobacteriosis has centered on the species Campylobacter jejuni, Campylobacter coli, the sister group to C. jejuni, is also a significant problem, but remains a much less studied organism. The purpose of this study was to develop and apply an expanded 16 locus MLST genotyping scheme to a large collection of C. coli isolates sampled from a wide range of host species, and to complete microarray comparative genomic hybridizations for these same strains, in order to: (1) determine whether host specific clones, genotypes, or clonal complexes are evident and (2) evaluate whether there are particular genes comprising the dispensable portion of the C. coli genome that are more commonly associated with certain host species. Genotyping and ClonalFrame analyses of the expanded MLST data suggest that (1) host preferred groups have tended to evolve in the diversification of C. coli, (2) this has happened repeatedly, at different times, throughout the evolutionary history of the species, and (3) recombination has played varying roles in the diversification of the different groups. Concomitant with the information on evolutionary history derived from the MLST data, the microarray data suggests that a combination of common ancestry in some cases and lateral gene transfer in others are behind a tendency for sets of genes to be common to isolates derived from particular hosts. Keywords: comparative genomic hybridization
2010-02-02 | GSE16787 | GEO
Project description:Spotted hyena (Crocuta crocuta) is the only extant species of the genus Crocuta, which once occupied a much wider range during the Pliocene and Pleistocene. However, its origin and evolutionary history is somewhat contentious due to discordances being found between morphological, nuclear, and mitochondrial data. Due to the limited molecular data from east Asian Crocuta, and the difficulty of extracting ancient DNA from this area, here we present proteomic analysis of cave hyenas from three locations in northern China. This marks the first proteomic data generated from cave hyenas, adding new molecular data to the east Asian populations. Phylogenetic analysis based on these protein sequences reveals two different groups of cave hyenas in east Asia, one of which could not be distinguished from modern spotted hyenas from northern Africa, tentatively the result of previously suggested gene flow between these lineages. With developments of instrumentation and analytical methods, proteomics holds promising potential for the phylogenetic reconstruction of ancient fauna previously thought to be unreachable using ancient DNA.
2020-10-19 | PXD020530 | Pride
Project description:A major challenge in biology is to determine how evolutionarily novel characters originate, however, mechanistic explanations for the origin of novelties are almost completely unknown. The evolution of mammalianM-BM- pregnancy is an excellent system in which to study the origin of novelties because extant mammals preserve major stages in the transition from egg-laying to live-birth. To determine the molecular bases of this transition we characterized the pregnant/gravid uterine transcriptome from tetrapods, including species in the three major mammalian lineages, and used ancestral transcriptome reconstruction to trace the evolutionary history of uterine gene expression. We show that thousands of genes evolved endometrial expression during the origins of mammalian pregnancy, including numerous genes that mediate maternal-fetal communication and immunotolerance.Furthermore we show that thousands of regulatory elements active inM-BM- decidualized human endometrial stromal cellsM-BM- are derived from ancient mammalian transposable elements which provided binding sites for transcription factors that mediate decidualization and endometrial cell-type identity.M-BM- Our results indicate that one of the defining mammalian novelties evolved via domestication of ancient mammalian transposable elements into hormone-responsive regulatory elements throughout the genome. Examination of histone modification and DNAse hypersensitivity in decidualized dESC
2015-01-30 | E-GEOD-61793 | biostudies-arrayexpress