Project description:Pathways underlying miRNA biogenesis, degradation, and activity were established early in land plant evolution, but the 24-nt siRNA pathway that guides DNA methylation was incomplete in early land plants, especially lycophytes. We show that the functional diversification of key gene families such as DICER-LIKE and ARGONAUTE (AGO) as observed in angiosperms occurred early in land plants followed by parallel expansion of the AGO family in ferns and angiosperms. We uncovered an unexpected AGO family specific to lycophytes and ferns. Our phylogenetic analyses of miRNAs in lycophytes, bryophytes, ferns, and angiosperms refined the temporal origination of conserved miRNA families in land plants.
Project description:A phylogenetic analysis of seven different species (human, mouse, rat, worm, fly, yeast, and plant) utilizing all (541) basic helix-loop-helix (bHLH) genes identified, including expressed sequence tags (EST), was performed. A super-tree involving six clades and a structural categorization involving the entire coding sequence was established. A nomenclature was developed based on clade distribution to discuss the functional and ancestral relationships of all the genes. The position/location of specific genes on the phylogenetic tree in relation to known bHLH factors allows for predictions of the potential functions of uncharacterized bHLH factors, including EST's. A genomic analysis using microarrays for four different mouse cell types (i.e. Sertoli, Schwann, thymic, and muscle) was performed and considered all known bHLH family members on the microarray for comparison. Cell-specific groups of bHLH genes helped clarify those bHLH genes potentially involved in cell specific differentiation. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique aspects of the evolution and functional relationships of the different genes in the bHLH gene family. PMID: 18557763 We used microarrays to determine bHLH expression in 20d rat Sertoli cells. RNA samples from two control groups (Sertoli cells cultured for 72 h) are compared to two treated groups (Sertoli cells cultured for 72 h with cAMP).
Project description:A phylogenetic analysis of seven different species (human, mouse, rat, worm, fly, yeast, and plant) utilizing all (541) basic helix-loop-helix (bHLH) genes identified, including expressed sequence tags (EST), was performed. A super-tree involving six clades and a structural categorization involving the entire coding sequence was established. A nomenclature was developed based on clade distribution to discuss the functional and ancestral relationships of all the genes. The position/location of specific genes on the phylogenetic tree in relation to known bHLH factors allows for predictions of the potential functions of uncharacterized bHLH factors, including EST's. A genomic analysis using microarrays for four different mouse cell types (i.e. Sertoli, Schwann, thymic, and muscle) was performed and considered all known bHLH family members on the microarray for comparison. Cell-specific groups of bHLH genes helped clarify those bHLH genes potentially involved in cell specific differentiation. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique aspects of the evolution and functional relationships of the different genes in the bHLH gene family. PMID: 18557763 We used microarrays to determine bHLH expression in 20d rat Sertoli cells.
Project description:Molecular clocks are the basis for dating the divergence between lineages over macro-evolutionary timescales (~104-108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes possess a clock-like behavior. This ‘epimutation-clock’ is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation-clocks recapitulate known topologies and branching times of intra-species phylogenetic trees in the selfing plant A. thaliana and the clonal seagrass Z. marina, which represent the two primary modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.
Project description:Molecular clocks are the basis for dating the divergence between lineages over macro-evolutionary timescales (~104-108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes possess a clock-like behavior. This ‘epimutation-clock’ is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation-clocks recapitulate known topologies and branching times of intra-species phylogenetic trees in the selfing plant A. thaliana and the clonal seagrass Z. marina, which represent the two primary modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.
2024-01-11 | GSE223810 | GEO
Project description:Phylogenetic and evolutionary studies of family Babyloniidae
Project description:Zika virus (ZIKV) is a mosquito-transmitted positive-sense RNA virus in the family Flaviviridae. ZIKV infections are associated with neurodevelopmental deficiencies termed Congenital Zika Syndrome. ZIKV strains are grouped into three phylogenetic lineages: East African, West African, and Asian, which contains the American lineage. RNA virus genomes exist as genetically-related sequences. The heterogeneity of these viral populations is implicated in viral fitness, and genome diversity is correlated to virulence. This study examines genetic diversity of representative ZIKV strains from all lineages utilizing next generation sequencing (NGS). Inter-lineage diversity results indicate that ZIKV lineages differ broadly from each other; however, intra-lineage comparisons of American ZIKV strains isolated from human serum or placenta show differences in diversity when compared to ZIKVs from Asia and West Africa. This study describes the first comprehensive NGS analysis of all ZIKV lineages and posits that sub-consensus-level diversity may provide a framework for understanding ZIKV fitness during infection.