Reticulation in evolution [Elektronische Ressource] / vorgelegt von Simone Linz

Reticulation in EvolutionInaugural-DissertationzurErlangung des Doktorgrades derMathematisch-Naturwissenschaftlichen Fakulta¨tder Heinrich-Heine-Universita¨t Dus¨ seldorfvorgelegt vonSimone Linzaus RheinbergMa¨rz 2008Aus dem Institut fu¨r Bioinformatikder Heinrich-Heine-Universit¨at Du¨sseldorfGedruckt mit der Genehmigung derMathematisch-Naturwissenschaftlichen Fakulta¨t derHeinrich-Heine-Universita¨t Du¨sseldorfReferent : Prof. Dr. Arndt von HaeselerKorreferenten : Prof. Dr. Martin Lercher und Assoc. Prof. Dr. Charles SempleTag der mu¨ndlichen Pru¨fung: 30. April 2008AbstractMolecular phylogenetics, the study of reconstructing evolutionary trees, is a well-estab-lished field of scientific endeavor. However, in certain circumstances evolution is not com-pletelytree-like. Forexample, acomparisonofgenetreesrepresenting aset ofpresent-dayspecies and reconstructed for different genetic loci often reveals conflicting tree topolo-gies. These discrepancies are not always due to missampling or difficulties in the genetree reconstruction method, but rather due to reticulation events such as horizontal genetransfer (HGT) and hybridization. During an HGT event, a DNA segment is transferredfrom one organism to another which is not its offspring, whereas hybridization describesthe origin of a new species through a mating between two different species. Both pro-cesses yield genomes that are mixtures of DNA regions derived from different ancestors.