bild 3 lecture 13

bild 3 lecture 13 - MITOCHONDRIA Eubacteria CHLOROPLASTS...

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Many of these organisms use hydrogen as an energy source and CO2 as an electron acceptor. They are the chief source of methane (natural gas) in the Earth's crust. Many in this group are able to live at high temperatures (hyperthermophiles). They use hydrogen as an energy source and sulfur compounds as electron acceptors. AND RELATED ORGANISMS Methanobacteri- um Fluorescent-labeled Sulfolobus on a sulfur crystal MITOCHON- DRIA CHLORO- PLASTS Chloro- flexus Anaerobic photo- synthesis appears Aerobic photo- synthesis { Cyanobacteria (blue-green algae) Flavo- bacteri- um (Oldest part of the tree) Bacillus anthracis (causes anthrax) Fungi Higher ani- mals Higher plants Water molds Red algae Sporozoans, such as the malaria- causing P. falciparum infecting red blood cells Green algae Plasmodia l slime molds Cellular slime molds Trypanosomes causes of sleeping sickness and leishmaniasis Mitochondria have been lost or modified in these organ- isms Electron trans- port evolves Photosynthesis re- peatedly gained and lost through symbioses with blue-green algae Eubacteria Eukaryotes All organisms are divided into three great domains, the Eubacteria (true bacteria), Archaea (bacteria-like organisms that live in a diversity of environments), and Eukaryotes (organisms made up of cells with a true nucleus). Note that mitochondria and chloroplasts were originally Eubacteria that came to live inside eukaryotic cells. This living together is called symbiosis . Evidence for horizontal gene transfer Phylogenetic trees are not always consistent with the Darwinian view of evolution as descent with modification. Inconsistent trees from the very oldest parts of the tree of life indicate that there was much horizontal gene transfer
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among different evolutionary lineages at a time when the three domains were beginning to diverge from each other. We know that horizontal gene transfer has taken place between the mitochondrial and chloroplast genomes and the genomes of their hosts. The vast majority of mitochondrial genes have been transferred into the host genome, leaving only 34 genes behind. Such horizontal transfers have taken place in non-mitochondrial genes as well. The picture below shows a phylogenetic tree of the Archaea and Eubacteria, with the best fit of about 40,000 genes that have been transferred horizontally among the various branches. About 600,000 genes that have been followed in this survey are regularly inherited by descent and form the main branches of the tree.
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This note was uploaded on 11/05/2008 for the course BILD BILD 3 taught by Professor Woodruff during the Spring '08 term at UCSD.

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bild 3 lecture 13 - MITOCHONDRIA Eubacteria CHLOROPLASTS...

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