Genetic evolution in action
January 26, 2011 in NEWS by Suzanne Elvidge
Symbiosis is a close and long-term interaction between two living organisms. This can be parasitic, such as mistletoe on an apple tree, commensal, such as barnacles on a scallop, or mutual, such as a lichen.
Aphis fabae by Michael Becker
Bacteria can be symbiotic – according to one theory, cell organelles may have evolved through endosymbiosis. As symbiotic bacteria are transmitted vertically (from parent to offspring), the genomes become reduced in size, and ‘gene-dense’. In a paper published in Genome Biology and Evolution, researchers from the University of Arizona looked at the black bean aphid (blackfly) mutual symbiont Serratia symbiotica. Compared with free-living relatives, these bacteria show massive reductions in genome size, similar to the reductions seen in ancient symbionts. These include large deletions, pseudogenes, and gene rearrangements.
Bats and plants have a mutual symbiotic relationship http://tinyurl.com/6969es8