John Logsdon over at Sex, Genes, and Evolution recommends a new book, The Origins of Genome Architecture by Michael Lynch. John also points us to a review article by Lynch [The Origins of Eukaryotic Gene Structure]. I second both recommendations. Read the article. Buy the book.
Here's a quotation from the article by Lynch,
Despite the enormous progress in molecular genetics over the past 50 years, no general theory for the evolution of the basic architectural features of genes has been formulated. Many attempts have been made to explain the features of genes, genomes, and genetic networks in the context of putatively adaptive cellular and/or developmental features, but few of these efforts have been accompanied by a formal evolutionary analysis. Because evolution is a population-level process, any theory for the origins of the genetic machinery must ultimately be consistent with basic population-genetic mechanisms. However, because natural selection is just one of several forces contributing to the evolutionary process, an uncritical reliance on adaptive Darwinian mechanisms to explain all aspects of organismal diversity is not greatly different than invoking an intelligent designer.Some of you will probably see why I like this guy! He warns against "uncritical reliance on adaptive Darwinian mechanisms."
This paper represents a first step toward the formal development of a general theory for the evolution of the gene that incorporates the universal properties of random genetic drift and mutation pressure. Although the ideas presented are unlikely to be correct in every detail, at a minimum they serve as a null model. For if verbal adaptive arguments are to provide confident explanations for any aspect of gene or genomic structure, something must be known about patterns expected in the absence of selection. This is a significant challenge because at this point it is difficult to reject the hypothesis that the basic embellishments of the eukaryotic gene originated largely as a consequence of nonadaptive processes operating contrary to the expected direction of natural selection. A significant area of future research will be to take these observations on gene and genome complexity to the next level, to evaluate whether natural selection is a necessary and/or sufficient force to explain the evolution of the cellular and developmental complexities of eukaryotes.Everyone needs to start paying attention. Random genetic drift is just as important for evolution as natural selection. That's not speculation. As far as I'm concerned, it's hard incontrovertible fact.
One of the "new ways" of looking at evolution is to consider mutation pressure, loosely defined as differences in the frequency of mutation. I'm not a big fan of this but it does emphasize that modern evolutionary theorists are thinking outside the Darwinian box—not surprising since Darwin died 125 years ago (today). I prefer mutationism, which is a way of emphasizing the imprtant role of mutation in directing evolution. Mutationism and mutation pressure are not the same thing.