●The zebrafish: a new model of T-cell and thymic development. Langenau, D. M. & Zon, L. I. Nature Reviews Immunology April (2005) This Review article discusses how zebrafish can be put to use as a genetic model for the development of the adaptive immune system.

●Evolutionary biology: the power of natural selection. Hendry, A. P. Nature 17 February (2005) Despite the central importance of natural selection in evolutionary biology, the strength of its influence on natural populations has long been a matter of debate. This News and Views article discusses these issues in the context of a recent study that proposes a new method of measuring selection.

●Insights into host responses against pathogens from transcriptional profiling. Jenner, R. G. & Young, R. A. Nature Reviews Microbiology April (2005)

●Calorie restriction, SIRT1 and metabolism: understanding longevity. Bordone, L. & Guarente, L. Nature Reviews Molecular Cell Biology April (2005)

●Mapping expression in randomized rodent genomes. Broman, K. W. Nature Genetics March (2005) This News and Views article discusses three recent studies that have used rodent recombinant inbred lines to investigate the genetic basis of variation in gene expression. This emerging field – known as 'genetical genomics' or 'expression genetics' – has great potential to increase our understanding of genetic disease.

●Communicating with Hedgehogs. Hooper, J. E. & Scott, M. P. Nature Reviews Molecular Cell Biology April (2005) This Review discusses new insights into Hedgehog signalling – a conserved component of many developmental pathways.

●Nature Reviews Applied Proteomics collectionNature Reviews Cancer, Nature Reviews Drug Discovery, Nature Reviews Genetics, Nature Reviews Microbiology, Nature Reviews Neuroscience, Nature Reviews Microbiology March (2005) This collection, and the accompanying web focus, feature a selection of Reviews, Perspectives and Highlights that explore the wide range of areas being revolutionized by the rapidly expanding field of proteomics, from advances in understanding normal cell function to applications in diagnostics and drug discovery. All articles in the web focus are free online until August 2005.