from the expectation that recent selection will have shaped divergence, and especially polymorphism, in and around the relevant sites. Using population genetic predictions of the response to selection of linked sites, it should be possible to conduct genomic scans of variation and divergence to identify the subset of polymorphic sites upon which to base an association mapping study. They demonstrate the method by looking at polymorphism within and divergence between Drosophila species.
Trudy Mackay et al., in “Genetics and Genomics of Drosophila Mating Behavior” (Chapter 16), also used a Drosophila model to identify genomic sites with interesting functions—mating behavior, in this case. Traditionally, genes that are directly involved in reproduction are not the easiest to study genetically, simply because mutants often have low reproductive success. These authors took the artificial selection approach and generated, over the course of 20 generations, two lines of Drosophila melanogaster that had high and low mean values for mating speed. They then conducted a microarray study to see which genes differed in expression level between the two divergently selected lines of flies.
The final paper in the volume takes an explicitly forward look and describes the ongoing and future changes that are happening to the biological sciences. With genomic sequences for many organisms having been available for several years, many biologists are turning to the highly integrated study of cellular processes and networks, a field that is called Systems Biology (Hood, 2003). Mónica Medina, “Genomes, Phylogeny, and Evolutionary Systems Biology” (Chapter 17), writes about how this nascent field is being shaped by the availability of genome sequences throughout the tree of life and of the kinds of questions about the evolution of networks that we can anticipate. Surely, just as Systems Biology emerges and qualitatively new kinds of insights emerge about how cells function, so too will emerge the field of Evolutionary Systems Biology with concomitant insights on the evolution of cell function.
Hood, L. (2003) Systems biology: Integrating technology, biology, and computation. Mech. Ageing Dev. 124, 9–16.