Thursday, September 28, 2006

Why do I like evolution in biological systems

One of my fascinations with biology are the amazingly different levels of abstraction one can choose to study biological systems. From molecular details and dynamics of proteins and RNA, with their different conformations and chemical activities to how these components interact with each other to produce the required functions inside the cell. The interactions of cells during development or bacterial communities. How firing neurons compute stimuli and produce behaviour and the interplay of species in ecosystems.

I guess what all of these things have in common is that, at any given level of abstraction, it is possible to describe components (i.e, atoms, proteins, cells) that can apparently be described with a reasonable limited set of properties. In all cases the interaction of the described components result in emergent complex patterns that are not easily predictable. All of this just means that we really don't know much about these systems :).

To complicate the story a little more these are evolving systems with constant genomic variability produced by mutation, recombination, segment and/or genome duplication events. How is this variability propagated through these layers of complexity ? What can be the consequences of a mutation ? Changing an amino acid in a protein might disrupt the binding to another cellular component. In turn this could alter a pathway, changing an oscillatory response to a transient one upon a certain environmental clue. This could be enough to modify the development and morphology of a species and how it relates to others in the ecosystem.

Given the slow nature of evolutionary change we can assume that in many cases we are studying a snapshot of it's dynamic nature. Like studying in much detail a frame of an ongoing movie. So, what is the point ? Understanding how something was "produced" helps us understand what to expect from it's functions. Also, understanding the impact of genome variability helps us determine to what extent biological features are conserved between species.

I'll try to devote some future posts on what is known about the impact of mutations and other genome changes in different levels of biological complexity.