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- Mikkelsen, Tarjei S, et al.
(författare)
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Genome of the marsupial Monodelphis domestica reveals innovation in non-coding sequences
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7141, s. 167-177
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Tidskriftsartikel (refereegranskat)abstract
- We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian ('marsupial') species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation.
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2. |
- Rivas, Daniel, et al.
(författare)
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Propagation-enhanced generation of intense high-harmonic continua in the 100-eV spectral region
- 2018
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Ingår i: Optica. - 2334-2536. ; 5:10, s. 1283-1289
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Tidskriftsartikel (refereegranskat)abstract
- The study of core electron dynamics through nonlinear spectroscopy requires intense isolated attosecond extremeultraviolet or even X-ray pulses. A robust way to produce these pulses is high-harmonic generation (HHG) in agas medium. However, the energy upscaling of the process depends on a very demanding next-generation laser technologythat provides multi-terawatt (TW) laser pulses with few-optical-cycle duration and controlled electric field.Here, we revisit the HHG process driven by 16-TW sub-two-cycle laser pulses to reach high intensity in the 100-eVspectral region and beyond. We show that the combination of above barrier-suppression intensity with a long generationmedium significantly enhances the isolation of attosecond pulses compared to lower intensities and/or shortermedia and this way reduces the pulse duration as well as field-stability requirements on the laser driver. This novelregime facilitates the real-time observation of electron dynamics at the attosecond timescale in atoms, molecules, andsolids.
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