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Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era.
BACKGROUND: Mirror therapy (MT) was found to improve motor function after stroke, but its neural mechanisms remain unclear, especially in single stroke patients.
OBJECTIVES: The following imaging study was designed to compare brain activation patterns evoked by the mirror illusion in single stroke patients with normal subjects.
METHODS: Fifteen normal volunteers and five stroke patients with severe arm paresis were recruited. Cerebral activations during movement mirroring by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Single-subject analysis was performed using SPM 8.
RESULTS: For normal subjects, ten and thirteen subjects displayed lateralized cerebral activations evoked by the mirror illusion while moving their right and left hand respectively. The magnitude of this effect in the precuneus contralateral to the seen hand was not dependent on movement speed or subjective experience. Negative correlation of activation strength with age was found for the right hand only. The activation pattern in stroke patients is comparable to that of normal subjects and present in four out of five patients.
CONCLUSIONS: In summary, the mirror illusion can elicit cerebral activation contralateral to the perceived hand in the majority of single normal subjects, but not in all of them. This is similar even in stroke patients with severe hemiparesis.
The Brassicaceae, including Arabidopsis thaliana and Brassica crops, is unmatched among plants in its wealth of genomic and functional molecular data and has long served as a model for understanding gene, genome, and trait evolution. However, genome information from a phylogenetic outgroup that is essential for inferring directionality of evolutionary change has been lacking. We therefore sequenced the genome of the spider flower (Tarenaya hassleriana) from the Brassicaceae sister family, the Cleomaceae. By comparative analysis of the two lineages, we show that genome evolution following ancient polyploidy and gene duplication events affect reproductively important traits. We found an ancient genome triplication in Tarenaya (Th-alpha) that is independent of the Brassicaceae-specific duplication (At-alpha) and nested Brassica (Br-a) triplication. To showcase the potential of sister lineage genome analysis, we investigated the state of floral developmental genes and show Brassica retains twice as many floral MADS (for MINICHROMOSOME MAINTENANCE1, AGAMOUS, DEFICIENS and SERUM RESPONSE FACTOR) genes as Tarenaya that likely contribute to morphological diversity in Brassica. We also performed synteny analysis of gene families that confer self-incompatibility in Brassicaceae and found that the critical SERINE RECEPTOR KINASE receptor gene is derived from a lineage-specific tandem duplication. The T. hassleriana genome will facilitate future research toward elucidating the evolutionary history of Brassicaceae genomes.