●Coots count. Andersson, M. Nature 3 April (2003) As this News and Views article reports, American coots can distinguish their own eggs from those laid by other females in the same nest.

●Progress and problems with the use of viral vectors for gene therapy. Thomas, C. E. et al. Nature Reviews Genetics May (2003)

●Alzheimer's disease: the cholesterol connection. Puglielli, L. et al. Nature Neuroscience April (2003)

●The circadian clock: pacemaker and tumour suppressor. Fu, L. & Lee, C. C. Nature Reviews Cancer May (2003) Circadian rhythms are daily oscillations in various biological processes that are regulated by an endogenous clock, the central component of which resides in the suprachiasmatic nucleus of the brain in mammals. Cell proliferation is regulated by circadian rhythm, and this review discusses how asynchrony in proliferation between normal and malignant tissues highlights the importance of the circadian clock in tumour suppression.

●Modelling brain diseases in mice: the challenges of design and analysis. Watase, K. & Zoghbi, H. Y. Nature Reviews Genetics April (2003)

●Drug discovery with engineered zinc-finger proteins. Jamieson, A. C. et al. Nature Reviews Drug Discovery May (2003) One strategy to control endogenous gene expression is to develop artificial transcription factors. Progress has been made in recent years in the design of transcription factors based on zinc-finger DNA-binding domains. This review considers how zinc fingers can be incorporated into new transcription factors, and describes key applications in drug discovery.

●Dopamine as chicken and egg. Self, D. Nature 10 April (2003) This News and Views article reports on the finding that dopamine triggers reward-seeking behaviour in rats.

●Reducing collateral damage. Steinman, L. Nature 17 April (2003) A News and Views article on repair by neural precursor cells in an experimental model of multiple sclerosis.

●Cortical neurons signal sound novelty. Moore, D. R. Nature Neuroscience April (2003) A News and Views article on how the brain processes novel sounds.

●Wise fathers. Reynolds, J. D. & Sheldon, B. C. Nature 17 April (2003) This News and Views article examines new findings that indicate that male bluegill sunfish adjust their behaviour towards their young according to how sure they are of being the real father.