Hidden breakpoints in genome alignments

During the course of evolution, an organism's genome can undergo changes that affect the large-scale structure of the genome. These changes include gene gain, loss, duplication, chromosome fusion, fission, and rearrangement. When gene gain and loss occurs in addition to other types of rearrangement, breakpoints of rearrangement can exist that are only detectable by comparison of three or more genomes. An arbitrarily large number of these "hidden" breakpoints can exist among genomes that exhibit no rearrangements in pairwise comparisons. We present an extension of the multichromosomal breakpoint median problem to genomes that have undergone gene gain and loss. We then demonstrate that the median distance among three genomes can be used to calculate a lower bound on the number of hidden breakpoints present. We provide an implementation of this calculation including the median distance, along with some practical improvements on the time complexity of the underlying algorithm. We apply our approach to measure the abundance of hidden breakpoints in simulated data sets under a wide range of evolutionary scenarios. We demonstrate that in simulations the hidden breakpoint counts depend strongly on relative rates of inversion and gene gain/loss. Finally we apply current multiple genome aligners to the simulated genomes, and show that all aligners introduce a high degree of error in hidden breakpoint counts, and that this error grows with evolutionary distance in the simulation. Our results suggest that hidden breakpoint error may be pervasive in genome alignments.Comment: 13 pages, 4 figure

Gesundheit um jeden Preis? Jüngste Reformen im französischen Gesundheitswesen

"Trotz einer strengen Kostenkontrolle im Rahmen nationaler Zielvorgaben ist das französische Krankenversicherungssystem seit den siebziger Jahren defizitär. Ein Kurswechsel in der Gesundheitspolitik im Jahr 2002 läutete die Ablösung des Prinzips der Kostenkontrolle durch eine Strategie der Nachfragekontrolle und einer verstärkten Beteiligung der Patienten an der Gesundheitsfinanzierung ein. Einsparungen sollen zudem durch die Einführung einer umfangs- und leistungsbezogenen Vergütung der Ärzte und Gesundheitseinrichtungen sowie eine Reorganisation des Behandlungsangebots zur Effektivitätssteigerung im Gesundheitswesen erzielt werden. Die Maßnahmen zur Effizienzsteigerung, insbesondere die Neustrukturierung der Gesundheitsverwaltung, stehen im Zeichen einer Stärkung der regulierenden Rolle des Staates im Gesundheitswesen, was bei den Berufsverbänden auf heftige Kritik stößt." (Autorenreferat)"In spite of a strict cost control in line with national target setting, the French health insurance system is in deficit since the 1970s. Within the reorientation of the health insurance policy in 2002, the cost control principle was replaced by a strategy of demand control and a strengthened patient participation in health financing. Furthermore, costs should be reduced by a new performance-related payment of doctors and health centers as well as by a reorganization of the treatment offer for an increase of efficiency in the public health system. These measures, especially the restructuring of the public health administration, are in line with a strengthening of state regulation in health care, which is severely criticized by health professionals." (author's abstract