@misc{JingAmbroseKnoxetal.2012, author = {Jing, Runchun and Ambrose, Michael A. and Knox, Maggie R. and Smykal, Petr and Hybl, Miroslav and Ramos, {\´A}. and Caminero, Constantino and Burstin, Judith and Duc, Gerard and van Soest, L. J. M. and Święcicki, W. K. and Pereira, M. Graca and Vishnyakova, Margarita and Davenport, Guy F. and Flavell, Andrew J. and Ellis, T. H. Noel}, title = {Genetic diversity in European Pisum germplasm collections}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {871}, issn = {1866-8372}, doi = {10.25932/publishup-43474}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434743}, pages = {367 -- 380}, year = {2012}, abstract = {The distinctness of, and overlap between, pea genotypes held in several Pisum germplasm collections has been used to determine their relatedness and to test previous ideas about the genetic diversity of Pisum. Our characterisation of genetic diversity among 4,538 Pisum accessions held in 7 European Genebanks has identified sources of novel genetic variation, and both reinforces and refines previous interpretations of the overall structure of genetic diversity in Pisum. Molecular marker analysis was based upon the presence/absence of polymorphism of retrotransposon insertions scored by a high-throughput microarray and SSAP approaches. We conclude that the diversity of Pisum constitutes a broad continuum, with graded differentiation into sub-populations which display various degrees of distinctness. The most distinct genetic groups correspond to the named taxa while the cultivars and landraces of Pisum sativum can be divided into two broad types, one of which is strongly enriched for modern cultivars. The addition of germplasm sets from six European Genebanks, chosen to represent high diversity, to a single collection previously studied with these markers resulted in modest additions to the overall diversity observed, suggesting that the great majority of the total genetic diversity collected for the Pisum genus has now been described. Two interesting sources of novel genetic variation have been identified. Finally, we have proposed reference sets of core accessions with a range of sample sizes to represent Pisum diversity for the future study and exploitation by researchers and breeders.}, language = {en} } @article{WangKirbyFurlongetal.2012, author = {Wang, E. and Kirby, E. and Furlong, K. P. and van Soest, M. and Xu, G. and Shi, X. and Kamp, P. J. J. and Hodges, K. V.}, title = {Two-phase growth of high topography in eastern Tibet during the Cenozoic}, series = {NATURE GEOSCIENCE}, volume = {5}, journal = {NATURE GEOSCIENCE}, number = {9}, publisher = {NATURE PUBLISHING GROUP}, address = {NEW YORK}, issn = {1752-0894}, doi = {10.1038/NGEO1538}, pages = {640 -- 645}, year = {2012}, abstract = {High topography in eastern Tibet is thought to have formed when deep crust beneath the central Tibetan Plateau flowed towards the plateau margin, causing crustal thickening and surface uplift(1,2). Rapid exhumation starting about 10-15 million years ago is inferred to mark the onset of surface uplift and fluvial incision(3-6). Although geophysical data are consistent with weak crust capable of flow(7,8), it is unclear how the timing(9) and amount of deformation adjacent to the Sichuan Basin during the Cenozoic era can be explained in this way(10,11). Here we use thermochronology to measure the cooling histories of rocks exposed in a section that stretches vertically over 3 km adjacent to the Sichuan Basin. Our thermal models of exhumation-driven cooling show that these rocks, and hence the plateau margin, were subject to slow, steady exhumation during early Cenozoic time, followed by two pulses of rapid exhumation, one beginning 30-25 million years ago and a second 10-15 million years ago that continues to present. Our findings imply that significant topographic relief existed adjacent to the Sichuan Basin before the Indo-Asian collision. Furthermore, the onset of Cenozoic mountain building probably pre-dated development of the weak lower crust, implying that early topography was instead formed during thickening of the upper crust along faults. We suggest that episodes of mountain building may reflect distinct geodynamic mechanisms of crustal thickening.}, language = {en} } @article{SchildgenEhlersWhippetal.2009, author = {Schildgen, Taylor F. and Ehlers, Todd and Whipp, David M. and van Soest, Matthijs C. and Whipple, Kelin X. and Hodges, Kip V.}, title = {Quantifying canyon incision and Andean Plateau surface uplift, southwest Peru : a thermochronometer and numerical modeling approach}, issn = {0148-0227}, doi = {10.1029/2009jf001305}, year = {2009}, abstract = {Apatite and zircon (U-Th)/He ages from Ocona canyon at the western margin of the Central Andean plateau record rock cooling histories induced by a major phase of canyon incision. We quantify the timing and magnitude of incision by integrating previously published ages from the valley bottom with 19 new sample ages from four valley wall transects. Interpretation of the incision history from cooling ages is complicated by a southwest to northeast increase in temperatures at the base of the crust due to subduction and volcanism. Furthermore, the large magnitude of incision leads to additional three-dimensional variations in the thermal field. We address these complications with finite element thermal and thermochronometer age prediction models to quantify the range of topographic evolution scenarios consistent with observed cooling ages. Comparison of 275 model simulations to observed cooling ages and regional heat flow determinations identify a best fit history with <= 0.2 km of incision in the forearc region prior to similar to 14 Ma and up to 3.0 km of incision starting between 7 and 11 Ma. Incision starting at 7 Ma requires incision to end by similar to 5.5 to 6 Ma. However, a 2.2 Ma age on a volcanic flow on the current valley floor and 5 Ma gravels on the uplifted piedmont surface together suggest that incision ended during the time span between 2.2 and 5 Ma. These additional constraints for incision end time lead to a range of best fit incision onset times between 8 and 11 Ma, which must coincide with or postdate surface uplift.}, language = {en} }