As we are so often reminded by proponents of Intelligent Design creationism, we contain molecular “machines” and “motors”. They don’t really explain how these motors came to be other than to foist the problem off on some invisible unspecified Designer, which is a poor way to do science—it’s more of a way to make excuses to not do science.
Evolution, on the other hand, provides a useful framework for trying to address the problem of the origin of molecular motors. We have a theory—common descent—that makes specific predictions—that there will be a nested hierarchy of differences between motors in different species. Phylogenetic analysis of variations between species allows us to reconstruct the history of a molecule with far more specificity than “Sometime between 6,000 and 4 billion years ago, a god or aliens (or aliens created by a god) conjured this molecule into existence by unknown and unknowable means”.
Richards and Cavalier-Smith (2005) have applied tested biological techniques to a specific motor molecule, myosin, and have used that information to assemble a picture of the phylogenetic history of eukaryotes.
Continue reading “Evolving motors” (on Pharyngula)