Microbes mimic Darwin finches
Also bacteria can trigger by acquiring new properties a adaptive radiation
An international research team has shown the example of the pathogen Bartonella that bacteria can adapt by acquiring a molecular injection needle for injecting bacterial proteins into host cells much more efficiently to new host organisms such as humans.
© University of Basel
The findings are of fundamental importance for understanding the evolution of novel pathogens of humans, the researchers said in the journal "PLoS Genetics'. But they also provide the first example of how bacteria can trigger a so-called "adaptive radiation" by acquiring new properties. Adaptive radiation describes the rapid emergence of a variety of species from a starting population as a result of specific adaptation to different ecological niches. This basic process of evolution contributes decisively to the development of biodiversity.
Adaptive radiations occur whenever an organism either an evolutionary bowl element newly acquired, by means of which it can quickly adapt to new niches, or when an organism with existing adaptive feature in a foreign environment meets with unoccupied niches.
Darwin finches: paradigm of adaptive radiation
The textbook example of such explosive speciation are running the Darwin finches on the Galápagos Islands. Through varied adaptation of beak shape so far 14 known species have evolved that can be used as diverse food sources. Other examples of adaptive radiations are found in reptiles, fish, insects and plants. However, so far we know comparatively little about this basic speciation in the ubiquitous bacteria.
Adaptive Raditionen in bacteria
Researchers at the University of Basel to the infection biologist Professor Christoph Dehio and the evolutionary biologist Professor Walter Salzburger who first described with international partners is a good example of adaptive radiation occupied in bacteria and decrypts its molecular basis. The scientists studied the speciation of the bacterial pathogen Bartonella, in which each of his many closely related species each specifically adapted to a particular mammalian host and thus to an ecological niche.
© Christoph Dehio
Parallel Evolution allows new insights into the emergence of new pathogens
The detailed study of the relationships of the Bartonella species surprisingly led to the detection of two parallel adaptive radiations, which have adapted to the same mammalian host descendants respectively of both radiations. Examples of parallel evolution facilitate the study of molecular mechanisms of evolution.
Molecular needle injected drug cocktail
The researchers were able to trace the parallel adaptive radiations of Bartonella on the independent acquisition of the same adaptive trait for host adaptation in their new study. This feature is a molecular injection needle that injects a custom to the corresponding mammalian host cocktail of bacterial proteins active in the infected host cells.
As also repeatedly specifically adapted to the human host organism Bartonella, the results are from the perspective of researchers in two ways important: On the one hand for the fundamental understanding of evolution of novel pathogens of humans, on the other hand with regard to the exploration of new approaches to combating these microbes. (PLoS Genetics online; doi: pgen.1001296)
(University of Basel, 14.02.2011 - DLO)
Search for related topics:
Biology adaptive radiation Evolution Biodiversity germs pathogens Darwin finches Galapagos Islands
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