Some of you might be interested in this recent study published in PLoS ONE about rapid evolutionary changes in morphology in rodents. I served as an academic editor on this interesting paper, that has gained quite a lot of media attention, e. g. in Science News and in Los Angeles Times. Since I was academic editor for this article, I was interviewed about it and I briefly comment upon it in the Science News article.
Although media attention and coverage is not, and should certainly not be, the only criterion for scientific "quality" (whatever that is!), it is further testimony of the advantage to publish in "Open Acess"-journals in general, and PLoS ONE in particular. This study is also interesting because it shows the value of museum collections as a source for ecological and evolutionary research, a point that Shawn Kuchta has repeatedly emphasized in our lab-meetings (and which I completely agree with, of course).
Oliver Pergams and his colleague Joshua Lawler used a large data set consisting of thousands of museum specimens, collected from various places of the world and during a long time period (more than a century) to track changes in morphology of the skull of rodents. They analyzed statistically which traits that changed, and how much. They further linked these morphological changes to two ecological factors: increasing urbanisation (i. e. increasing local human population densities) and climatic factors.
They found that both urbanisation and climatic factors were statistically significantly related to the morphological changes they observed. Although not all these morphological changes are understood from a functional viewpoint, and the genetic basis of the changes are not known, the study is strongly suggestive. Rapid evolution in rodents might thus be a result of both humans directly, and possibly indirectly through anthroprogenic climate change.
When I made a blog item about this PLoS article I put a question mark after "evolution" in the headline. A reader made a still more qualifying comment: are morphological changes per se proving evolution?
ReplyDeleteWithin a short time, maybe two generations, people in some countries have been taller because of better nutrition (take some East Asians, like South Koreans) but that has not been followed by evolutionary changes which can be spotted in the genetical code (or am I wrong there?). Could it be the same for mice and men? As an amateur in this area I am a bit confused.
That's an excellent question. No, we do not insist in the paper that these size changes must be due to natural selection, rather we discuss in detail that these changes may also be due to phenotypic plasticity (as in your nutrition example) or migration.
ReplyDeleteBjörn/Oliver:
ReplyDeleteThis is an excellent point by Björn, and as a matter of fact, I pointed out that myself as an academic editor (although I admit that made the same mistake myself in my blog entry above!). These changes might reflect evolutionary changes, or they might not, but I think that Oliver and his colleague should not be blamed for not answering this question too (that must be something for future studies to adress).