Monday, July 12, 2010

Complexity made simply

The European Evo-Devo association meeting has ended, after many very interesting presentations and posters by the 450 attendees. The topics ranged from microbes to plants to humans, and from relatively simple phenotypes to more obviously complex ones.

Major attention was given to the neural crest and its evolution, as seen in comparative development and in the fossil record (because neural-crest-related tissues are known and can be explored in some kinds of fossils, and because, at least in the opinion of one speaker, the neural-crest is what's interesting about vertebrates). The neural crest is a 4th primary, or 'germ' tissue layer in vertebrates and is important in many of our structures, especially on the outside, like hair, teeth, scales, nipples and others.

Many papers dealt with morphometrics and their genetic basis and evolution, and plasticity and the importance of the environment in more and more aspects of development. Scott Gilbert, in particular, stressed this, but so did others. Jose Maria Gomez from Spain reported on studies of the shape of flower petals and their relative ability, in different environments in Spain, to attract particular species of pollinating insects. Another speaker studied the evolution of details of fruit-fly wing shape and how it is affected by ambient temperature during development. Several talks were about vertebrate morphology (Ken talked about the skull, representing the research group we're in). Chris Thompson discussed the aggregation of otherwise-independent cells in the slime mold Dictyostelium to form fruiting bodies in which only a subset of the cells actually reproduce--why would they do that? His interest is in the evolution of cooperation and cheating.

One major point we made in our book was that from what we now know about developmental genetics, the processes can be rather straightforward and understandable even for complex traits. We referred to this as 'complexity made simply'. The papers at this meeting showed that research in developmental biology continues to support this idea. Traits that involve many different genes and seem complex in that sense, can be made simply, in the sense that the signaling among different types of cells that is the basis of the trait's development is a simple logical process of information exchange. For example, many different genes are involved in the sending or receiving of a chemical signal (such as a growth factor), but it is the sending and receiving of the signal that is most important.

We're reporting from a rural bed and breakfast in northern France, where we're traveling. And we hope to have more opportunities to post in the next week before our return. But the gist of the meeting on Evo-Devo research is that the science continues to document the ways in which identifiable factors interact in 4-dimensional ways in space and time among cells within organisms, and among organisms in ecological systems, to generate the forms of Nature.

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