New mechanism that causes some changes in DNA content has been found by a group of Uppsala University scientists and it is due to something has happened in bacteria that live as a parasite inside the cells of other organisms.
Change in the amount of DNA in the chromosomes of bacteria can be either by gene amplification and gene deletion by which the amount is increasing and decreasing respectively.
Currently a genetic analysis on salmonella mutant done by a PhD student, Sanna Koskiniemi has shown that in order for spontaneous deletions are to take placed in the bacteria a special type DNA-synthesizing enzyme must be present. The decreased or increased rates of deletion up to 30 times are proven by genetically inactivating or overproducing these enzymes.
Professor Dan Andersson suggests that bacteria that live either as parasites inside cells or in symbiosis with other organisms are of special interest with regard to this new mechanism. As DNA has disappeared during evolution, thus, these bacteria often have small chromosomes. With these new findings we can better understand and predict how DNA is eliminated from chromosomes.
Link to the original article:
http://www.sciencedaily.com/releases/2009/06/090608182541.htm
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