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The evolutionary origins of hydrogenosomes have been the subject of considerable debate. From early days it was apparent that hydrogenosomes had evolved on multiple occasions in different eukaryotes, but from which progenitor organelle or endosymbiont was unresolved. Work from many different laboratories has contributed towards formulating the current hypothesis that hydrogenosomes and mitosomes, their even more reduced cousins, share common ancestry with mitochondria. Their shared similarities, for example their common mechanisms of protein import and their double membrane, can be explained by common ancestry, and their differences by descent with modification under contrasting lifestyles. The hypothesis that mitochondria, mitosomes and hydrogenosomes are homologues, predicts that, as the organelles are studied more deeply, additional shared features will be revealed.
However, it is already apparent from the contributions to this volume, that identifying the genetic contribution to eukaryotes of the mitochondrial endosymbiosis, and revealing the functions of its descendent organelles, are key to understanding eukaryotic biology and evolution.
Table des matières
The Road to Hydrogenosomes.- Mitochondria: Key to Complexity.- Origin, Function, and Transmission of Mitochondria.- Mitochondria and Their Host: Morphology to Molecular Phylogeny.- Anaerobic Mitochondria: Properties and Origins.- Iron-Sulfur Proteins and Iron-Sulfur Cluster Assembly in Organisms with Hydrogenosomes and Mitosomes.- Hydrogenosomes (and Related Organelles, Either) Are Not the Same.- The Chimaeric Origin of Mitochondria: Photosynthetic Cell Enslavement, Gene-Transfer Pressure, and Compartmentation Efficiency.- Constantin Merezhkowsky and the Endokaryotic Hypothesis.- The Diversity of Mitochondrion-Related Organelles Amongst Eukaryotic Microbes.- Mitosomes of Parasitic Protozoa: Biology and Evolutionary Significance.
Résumé
The evolutionary origins of hydrogenosomes have been the subject of considerable debate. From early days it was apparent that hydrogenosomes had evolved on multiple occasions in different eukaryotes, but from which progenitor organelle or endosymbiont was unresolved. It is already apparent from the contributions to this volume, that identifying the genetic contribution to eukaryotes of the mitochondrial endosymbiosis, and revealing the functions of its descendent organelles, are key to understanding eukaryotic biology and evolution. This book closes the gap between the endosymbiotic theory for the origin of organelles and their incorporation into evolutionary theory.
