Lab-meeting about high-altitude adaptation in humans

It is time for a new lab-meeting on Wednesday (September 1), and this time I was thinking that we should discuss a recent Science-paper where the auhtors present evidence for genetic adaptations to high-altitude living in Tibet. The paper can be downloaded here. Interestingly, there is also another recent study on the same topic in PNAS, which can be downloaded here. I suggest we read both of them in preparation for the lab-meeting on Wednesday.

These papers has received quite a lot of attention both in media and in the bloggosphere. I can recommend population geneticist Jerry Coynes blogpost about one of these papers on his excellent blog "Why Evolution is true". Coyne has also a more critical blogpost where he cautions against solely relying on statistical approaches on gene frequency changes to infer selection. Being an experimental evolutionary biologist and ecologist by heart, I could of course not agree more with Coyne.

Time of lab-meeting as usual: 10.15 in "Darwin", Wednesday September 1, 2010. Any fika-volunteer?

Also, do not forget that CAnMove organises a barbecue on the same day in the afternoon at 17.00 at the Biology Department. Contact Sophia Engel for more info.


References and publication details:

Genetic Evidence for High-Altitude Adaptation in TibetTatum S. Simonson, Yingzhong Yang, Chad D. Huff, Haixia Yun, Ga Qin, David J. Witherspoon, Zhenzhong Bai, Felipe R. Lorenzo, Jinchuan Xing, Lynn B. Jorde, Josef T. Prchal, and RiLi Ge Science 2 July 2010 329: 72-75; published online 13 May 201013 May 2010 [DOI: 10.1126/science.1189406] (in Reports)

Natural selection on EPAS1 (HIF2α) associated with low hemoglobin concentration in Tibetan highlanders PNAS 2010 107 (25) 11459-11464; published ahead of print June 7, 2010, doi:10.1073/pnas.1002443107

Lab-meeting on adaption, extinction and GIS and field excursion next week

This coming week, I was thinking that we should discuss two interesting and general papers. The first one is an essay entitled Adaptation, extinction and plasticity in a changing environment, and it is published in the journal PLoS Biology. One of the authors is Russel Lande, one of the pioneers in developing statistical methods to study natural and sexual selection in natural populations. The current paper outlines a new research programme in how to apply these methods to study ongoing adaptation and evolutionary change in response to rapid environmental change, e. g. due to anthroprogenic global warming.

The second paper is published in Trends in Ecology & Evolution and it is entitled Integrating GIS-based environmental data in to evolutionary biology. One of the authors is John Wiens, who has used GIS extensively in some recent impressive and interesting studies on niche conservatism in salamanders and amphibians, some of which we have discussed in previous lab-meetings. The choice of this latter paper is motivated by the fact that Maren Wellenreuther and Keith Larson have done some interesting new analyzes using GIS that we might take a look at, depending on time and if Maren kan make it to the lab-meeting.

For Thursday (May 20), I was thinking that some of us should make a field trip to Klingavälsåns Naturreservat and other damselfly sites. Although spring is late, we could at least go out in the field and look at the sites and do some planning. We can decide about time and practical details on Wednesday.

Time and place for our regular lab-meeting:

Where: "Darwin-room", 2nd floor, Ecology Building
When: Wednesday, May 19, 10.15.

Any fika-volunteer?

The toucan bill as a thermal radiator: adaptation or exaptation?

Have you ever visited a rainforest in the New World, such as in Costa Rica or elsewhere in Latin America? If so, it is a great chance you have seen a toucan, those big fruit eating birds with HUGE bills (see picture above).

The function of such large bills has been quite unknown, but now a new study published in Science indicates a surprising novel function: the bill might be important as thermal radiator (bottom figure). Using a thermal image camera of similar kind as we have bought to our lab, the researchers were able to demonstrate that the many blood vessels in the bill helped to quickly cool down the bird and get rid of excess heat. The birds could actually cool down by ten degrees in only a few minutes (yellow areas are high temperature areas in the bottom picture).

This study is interesting for several reasons. First, it shows how new techniques can help to answer old questions and give new answers (sometimes quite surprising, as in this case). Second, it shows that one has to have an open mind when trying to understand the adaptive functions of traits and what traits are "for". Most people, including myself, probably thinks that the bill evolved "for" the specific purpose of efficiently picking fruit. This might very well be the case, but once the bill have reached a certain size, it can also secondarily get another function in the form of a thermoregulator.

In this context, perhaps the thermoregulatory function is simply an exaptation, i. e. not a true adaptation in the language of paleontologist Stephen Jay Gould? Or perhaps the bill was further exaggerated once it had reached its "optimum" size from the perspective of fruit picking, and only the extra length is a true adaptation in the context of thermoregulation? Perhaps future phylogenetic comparative studies involving other toucan species with different bill sizes and the thermal image camera can provide some answers to these fascinating questions?

(Thanx Maren for the tip!)