Systems Microbiolo16

Systems Microbiolo16 - ° Also very few repeats ° This...

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Systems Microbiology o You can extract the DNA of these symbionts and assemble the whole genome ° The genome is a lot smaller, since they don’t have to live out in the environment ° Somewhere around 400 kilobase pairs o These Buchnera endosymbionts are derived from E. coli ° We can reconstruct a common ancestor, which would have looked very much like E. coli ° The gene loss must have happened very rapidly ° This process is described in a paper by Siv Andersson ° After 70 million years, there are no chromosomal rearrangements or gene acquisitions ° But considerable sequence divergence does occur ° They’re changing around 2000 times faster ° Accumulation of pseudo-genes restrict the diet of the aphids ° The evolutionary dynamic is very different – there isn’t any rearrangement ° Many fewer non-synonymous substitutions occur
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Unformatted text preview: ° Also very few repeats ° This sort of genome reduction can get really extreme, as long as the host relationship is stable enough ° The symbiont has lost the ability to regulate its own gene control – it doesn’t have the mechanisms that free-living bugs like E. coli have, so it can’t make more or less amino acids depending on the diet that the aphid is on ° Another system: Baumannia and Sulcia in the Glassy-winged Shapshooter o The genomes are pretty similar to Buchnera o You have to think of the insect like an ecosystem o One wonders: how much are there similar things going on in out own systems? o For example, it looks like human genetics determines which bacteria live in our stomach and intestines, which influences obesity....
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This note was uploaded on 01/24/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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