ScienceDaily (Feb. 8, 2010) — Monash University biochemists have found a critical piece in the evolutionary puzzle that explains how life on Earth evolved millions of centuries ago.
The team, from the School of Biomedical Sciences, has described the process by which bacteria developed into more complex cells and found this crucial step happened much earlier in the evolutionary timeline than previously thought.
Artist's rendering of cell structure. New research explains how mitochondria -- the power house of human and other cells, which provide complex eukaryotic cells with energy and ability to produce, divide and move -- were thought to have evolved about 2000 million years ago from primitive bacteria. (Credit: iStockphoto/Sebastian Kaulitzki)
Team leader and ARC Federation Fellow Trevor Lithgow said the research explained how mitochondria -- the power house of human and other cells, which provide complex eukaryotic cells with energy and ability to produce, divide and move -- were thought to have evolved about 2000 million years ago from primitive bacteria.
"We have now come to understand the processes that drove cell evolution. For some time now the crux of this problem has been to understand how eukaryotes first came to be. The critical step was to transform small bacteria, passengers that rode within the earliest ancestors of these cells, into mitochondria, thereby beginning the evolution of more complex life-forms," Professor Lithgow said.
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Science 5 February 2010:
Vol. 327. no. 5966, pp. 649 - 650
DOI: 10.1126/science.1182129
Evolution:
Tinkering Inside the Organelle
Among the questions about the evolution of eukaryotes is the debate over how they acquired the membrane-bound organelle, mitochondria. Mitochondria produce energy in nearly all eukaryotic cells (1) and regulate cell metabolism by controlling the flow of factors such as ions, amino acids, and carbohydrates between themselves and the cytoplasm. Mitochondria evolved from a bacterial endosymbiont (an
-proteobacterium), and this process depended on the establishment of new pathways that facilitated the import of proteins into and across the double membrane (inner and outer) of the ancestral endosymbiont. Herein lies a debate: How did the process of protein import in mitochondria—which facilitated the evolution of this organelle, and thus, eukaryotic cell evolution—arise? Was the process driven by the ancestral host cell or by the prokaryotic endosymbiont, or by both? Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne 3800, Australia.
E-mail: trevor.lithgow@med.monash.edu.au
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