659 research outputs found
Codonopsis pilosula twines either to the left or to the right
We report the twining handedness of Codonopsis pilosula, which has either a left- or right-handed helix among different plants, among different tillers within a single plant, and among different branches within a single tiller. The handedness was randomly distributed among different plants, among the tillers within the same plants, but not among the branches within the same tillers. Moreover, the handedness of the stems can be strongly influenced by external forces, i.e. the compulsory left and right forming inclined to produce more left- and right-handed twining stems, respectively, and the reversing could make a left-handed stem to be right-handed and vice versa. We also discuss the probable mechanisms these curious cases happen
A Genome-Wide Analysis Reveals Significant Overlap of Transcription and DNA Repair in Stationary Phase Yeast
The association between transcription and DNA repair is acknowledged as a player in the generation of mutations in a non-random fashion in prokaryotes and eukaryotes. Previous studies demonstrated that the transcription complex is capable of directing DNA repair to sites of transcription. This process is especially important to growth-arrested cells, in which many DNA repair capacities are diminished; it may also lead to mutations preferentially in transcribed genes. Using microarray analysis of growth-arrested yeast cultures, we demonstrated on a genomic scale, the co-localization of a DNA-turnover marker, indicative of DNA-repair-associated DNA synthesis, with genes persistently transcribed during stationary phase. This may serve as a clue regarding the non-random manner in which non-dividing cells may potentially mutate in the absence of replication, solely as a result of their inherent, transcriptional stress response
Transcriptome Comparative Profiling of Barley eibi1 Mutant Reveals Pleiotropic Effects of HvABCG31 Gene on Cuticle Biogenesis and Stress Responsive Pathways
Wild barley eibi1 mutant with HvABCG31 gene mutation has low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. To better understand how such a mutant plant survives, we performed a genome-wide gene expression analysis. The leaf transcriptomes between the near-isogenic lines eibi1 and the wild type were compared using the 22-k Barley1 Affymetrix microarray. We found that the pleiotropic effect of the single gene HvABCG31 mutation was linked to the co-regulation of metabolic processes and stress-related system. The cuticle development involved cytochrome P450 family members and fatty acid metabolism pathways were significantly up-regulated by the HvABCG31 mutation, which might be anticipated to reduce the levels of cutin monomers or wax and display conspicuous cuticle defects. The candidate genes for responses to stress were induced by eibi1 mutant through activating the jasmonate pathway. The down-regulation of co-expressed enzyme genes responsible for DNA methylation and histone deacetylation also suggested that HvABCG31 mutation may affect the epigenetic regulation for barley development. Comparison of transcriptomic profiling of barley under biotic and abiotic stresses revealed that the functions of HvABCG31 gene to high-water loss rate might be different from other osmotic stresses of gene mutations in barley. The transcriptional profiling of the HvABCG31 mutation provided candidate genes for further investigation of the physiological and developmental changes caused by the mutant
Species interslope divergence of ants caused by sharp microclimatic stresses at ‘Evolution Canyon’ II, Lower Nahal Keziv, western Upper Galilee, Israel
Species diversity of ants was recorded in 2000–2001 at seven stations of a microsite in Nahal Keziv, western Upper Galilee, designated as ‘Evolution Canyon’ II. In the 7000 m2 area, we recorded 31 ant species including one species identified only at the genus level: 19 on the ‘African’ slope, 12 on the ‘European’ slope, and 17 species at the valley bottom. Among the recorded species one is new to the fauna of Israel (Cataglyphis semitonsus). Interslope ant species composition varies remarkably due to differential microclimatic conditions, partly demonstrating the effect of microclimate differences on ant species diversity at a microscale. Further studies at this site following the ‘Evolution Canyon’ model as conducted at EC I in Mount Carmel, will enable in-depth investigations of changes in biodiversity, adaptation and incipient sympatric speciation, i.e. evolution in action, within a relatively free breeding interslope populations.
Cite as: Finkel, M., Ofer, J., Beharav, A. & Nevo, E. 2015. Species interslope divergence of ants caused by sharp microclimatic stresses at ‘Evolution Canyon’ II, Lower Nahal Keziv, western Upper Galilee, Israel. Israel Journal of Entomology 44–45: 63–73.
DOI: 10.5281/zenodo.31645
urn:lsid:zoobank.org:pub:097AE3D0-19FF-4787-B236-924856DC6A5
The genus Cystolepiota (Agaricaceae, Basidiomycetes) in Israel
The genus Cystolepiota is new for Israel. In Israel it is represented by two species: Cystolepiota bucknallii and C. moelleri. Locations, dates of collections in Israel, general distribution, detailed macro- and micromorphological descriptions and illustrations are given
Mapping of the eibi1 gene responsible for the drought hypersensitive cuticle in wild barley (Hordeum spontaneum)
Segregation analysis showed that eibi1, a drought hypersensitive Cuticle wild barley mutant, was monogenic and recessive, and mapped in two F, Populations, one made from a cross between the mutant and a Cultivated barley (cv. Morex), and the other between the mutant and another wild barley. A microsatellite marker screen showed that the gene was located oil barley chromosome 3H, and a set of markers already assigned to this chromosome, including both microsatellites and ESTs, was used to construct a genetic map. eibi1 co-segregated with barley EST AV918546, and was located to bin 6. The synteny between barley and rice ill this region is incomplete, with a large discrepancy in map distances, and the presence Of Multiple inversions
Transcriptome sequencing and phylogenomic resolution within Spalacidae (Rodentia)
BACKGROUND: Subterranean mammals have been of great interest for evolutionary biologists because of their highly specialized traits for the life underground. Owing to the convergence of morphological traits and the incongruence of molecular evidence, the phylogenetic relationships among three subfamilies Myospalacinae (zokors), Spalacinae (blind mole rats) and Rhizomyinae (bamboo rats) within the family Spalacidae remain unresolved. Here, we performed de novo transcriptome sequencing of four RNA-seq libraries prepared from brain and liver tissues of a plateau zokor (Eospalax baileyi) and a hoary bamboo rat (Rhizomys pruinosus), and analyzed the transcriptome sequences alongside a published transcriptome of the Middle East blind mole rat (Spalax galili). We characterize the transcriptome assemblies of the two spalacids, and recover the phylogeny of the three subfamilies using a phylogenomic approach. RESULTS: Approximately 50.3 million clean reads from the zokor and 140.8 million clean reads from the bamboo ratwere generated by Illumina paired-end RNA-seq technology. All clean reads were assembled into 138,872 (the zokor) and 157,167 (the bamboo rat) unigenes, which were annotated by the public databases: the Swiss-prot, Trembl, NCBI non-redundant protein (NR), NCBI nucleotide sequence (NT), Gene Ontology (GO), Cluster of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 5,116 nuclear orthologous genes were identified in the three spalacids and mouse, which was used as an outgroup. Phylogenetic analysis revealed a sister group relationship between the zokor and the bamboo rat, which is supported by the majority of gene trees inferred from individual orthologous genes, suggesting subfamily Myospalacinae is more closely related to subfamily Rhizomyinae. The same topology was recovered from concatenated sequences of 5,116 nuclear genes, fourfold degenerate sites of the 5,116 nuclear genes and concatenated sequences of 13 protein coding mitochondrial genes. CONCLUSIONS: This is the first report of transcriptome sequencing in zokors and bamboo rats, representing a valuable resource for future studies of comparative genomics in subterranean mammals. Phylogenomic analysis provides a conclusive resolution of interrelationships of the three subfamilies within the family Spalacidae, and highlights the power of phylogenomic approach to dissect the evolutionary history of rapid radiations in the tree of life
Ancient polymorphisms and divergence hitchhiking contribute to genomic islands of divergence within a poplar species complex
How genome divergence eventually leads to speciation is a topic of prime evolutionary interest. Genomic islands of elevated divergence are frequently reported between diverging lineages, and their size is expected to increase with time and gene flow under the speciation-with-gene-flow model. However, such islands can also result from divergent sorting of ancient polymorphisms, recent ecological selection regardless of gene flow, and/or recurrent background selection and selective sweeps in low-recombination regions. It is challenging to disentangle these nonexclusive alternatives, but here we attempt to do this in an analysis of what drove genomic divergence between four lineages comprising a species complex of desert poplar trees. Within this complex we found that two morphologically delimited species, Populus euphratica and Populus pruinosa, were paraphyletic while the four lineages exhibited contrasting levels of gene flow and divergence times, providing a good system for testing hypotheses on the origin of divergence islands. We show that the size and number of genomic islands that distinguish lineages are not associated with either rate of recent gene flow or time of divergence. Instead, they are most likely derived from divergent sorting of ancient polymorphisms and divergence hitchhiking. We found that highly diverged genes under lineage-specific selection and putatively involved in ecological and morphological divergence occur both within and outside these islands. Our results highlight the need to incorporate demography, absolute divergence measurement, and gene flow rate to explain the formation of genomic islands and to identify potential genomic regions involved in speciation.Publisher PDFPeer reviewe
- …
