The perils of symbiosis

An interest area of mine are parasites. Not normal parasites, that just feeds of other creatures, but the type of parasites that actually can influence their hosts. Carl Zimmer has written an entire book about it, and has also written some good stuff about them on his blog.

A natural extension of that interest would be symbiosis, where two (or more) creatures are somewhat inter-dependent. I haven't really gotten into this subject though, even though the whole concept is rather facinating. Much of that might have to do with the fact that symbiosis is rarely as dramatic as parasites, since both types of creatures depend upon each other for mutual survival. Or so I thought.

One aspect I hadn't thought of, was the fact that since these creatures are inter-dependent, mutations in indviduals from one of the species, can have drastic effects on individuals from the other species. That's what a new paper in PLoS Biology shows us.

PLoS Biology has been kind enough to make a synopsis of the study for us non-biologists, and the findings sounds facinating.

Imagine having bacteria dictate how well you fare under extreme conditions. For the aphid Acyrthosiphon pisum, that’s the price it pays for getting the nutrients it needs. This little insect, which survives by sucking juices out of the stems of grain crops and other vegetation, depends on a bacterial sidekick, Buchnera aphidicola, for amino acids it can’t get from plants. The aphid in turn provides the bacterium with energy and carbon as well as shelter inside specialized cells.

Such interdependent relationships are not unusual in the natural world. What is unusual, report Helen Dunbar, Nancy Moran, and colleagues in a new study, is that a single point mutation in Buchnera’s genome can have consequences for its aphid partner that are sometimes detrimental, and sometimes beneficial.

Basicly, the finding is that a certain mutation in Buchnera aphidicola can have a large effect on the host Acyrthosiphon pisum ability to withstand heat. On the other hand, in cooler areas, the same mutation can be benificial.

Normally I would link to the study as well, and not only the synopsis, but PLoS Biology is really slow for me today, so I can't access the article.