Within the microbial world, is the degree of pleiotropy displayed by an organism inversely related to its genome size?
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Let me see if I got it right: you mean to ask if for greater genome sizes, there is fewer pleiotropy going on? Hmmm... some say that pleiotropy is inversely related to the evolutionary rate of genes - I wonder how true is that. On the condition that this is the case, AND if some microbes accumulate some "junk" DNA (over time) that increases their genome dimension, then I can see how the answer to your query is yes.
Higher level of pleiotropy -> lower gene evolutionary rate -> lower adaptation to new conditions -> genome size may keep on growing with unnecessary bits and pieces.
I speculate that it is not that simple though. If I had to gamble than I would bet on some kind of a bell curve for this pleiotropy - genome size relation. After a wile, you just can't do it no more and despite the higher pleiotropy degree of display, you either push up the gene evolutionary rate or vanish.
I would love to hear some other answers and your thoughts as well.
Posted by: Ami Bachar | October 06, 2011 at 01:14 PM