Reviews & Analysis

Variation in life-history strategies is a target for natural selection, and there are many trade-offs between optimal values for different life-history traits. Genomic approaches are starting to contribute to our understanding of the mechanistic basis of these trade-offs.

The structure and function of many tissues depends on cells being polarized along several axes. Frizzled/planar cell polarity signalling is a conserved mechanism that establishes such polarity in cells through the asymmetric distribution of its components.

Gene expression is regulated by an intricate interplay of many factors at different levels. To understand how the currently observed expression patterns have evolved, we need to understand the evolution of the individual regulators and the complex regulatory networks that they form.

A dynamic view of nuclear function is emerging, in which genomic regions undergo repositioning relative to each other and to nuclear subcompartments. Increasing evidence points to an important contribution of these movements in the regulation of gene expression.

Genome sequencing, antigenic mapping and epidemiological modelling are enhancing our understanding of the evolution of human influenza virus. However, the full picture will require a genomic view of genetic diversity, including the acquisition of polymorphism data from within hosts and from diverse geographical regions.

Gene expression levels are adjusted to compensate for the different numbers of sex chromosomes in males and females, although the mechanisms for doing this vary between species. Recent data show how dosage compensation is fine-tuned by modulating chromatin structure.

This article argues that recombination has a far more important role in the evolution of plant genomes than is currently appreciated, and that genome-wide patterns of recombination might explain some intriguing differences between plant and animal genomes.

The mouse is a powerful model for elucidating the genetic basis of complex human traits and diseases. One reason for this is the wealth of available resources for mouse genetics that has been built up over the past 100 years.

Heterochromatin was once considered the less-interesting part of the genome, the junk that had to be dealt with by being silenced. Recent studies in fission yeast indicate that heterochromatin has a role in various chromosomal processes, including transcription, chromosome segregation and long-range chromatin interactions.

Recent progress has changed our view of how Polycomb group complexes are recruited and how they affect chromatin and repress gene activity. The authors review our current understanding of PcG mechanisms and their implications for the programming of gene expression in development.