Opinion in 2006

Using cancer as an example of complex disease, the authors revisit the evidence for the hypothesis that human diseases result from interactions between genetic variants and the environment.

The ability to provide information about variants in genes is crucial to genome-wide association studies. This article argues that the currently available marker sets are unlikely to provide adequate coverage of genic variants, and suggests how this problem could be overcome.

Gene–environment interactions are key contributors to complex disease, but are hard to dissect in commonly used case–control designs. This article argues that large-scale prospective cohort studies, several of which are planned or under way, provide an essential alternative strategy.

Evolutionary theory denies the existence of competition between genetically identical cells. But cell–cell competition undeniably occurs at different levels in many organisms, suggesting that it is either itself advantageous or a relic of an advantageous process.

The ability to integrate data from different sources is crucial in many areas of biological research, particularly systems biology. This article argues that problems with life-science databases are holding back research, and proposes some practical solutions.

Many of the already characterized non-coding RNAs, including small interfering RNAs, microRNAs and small nucleolar RNAs, guide or target RNP complexes to specific nucleic-acid sequences. How did such chimeric RNA–protein enzymes evolve? And why are they common in some but not other organisms?

Multifactorial disorders have grabbed the limelight in recent years, at the expense of research on monogenic traits. This shift in emphasis might not be fully justified, given the insight that seemingly 'simple' disorders can bring to genome function and complex disease aetiology.

A growing body of evidence indicates that epigenetic states can be influenced by the environment. Considering that erasure of epigenetic marks between generations is not universal among multicellular organisms, what are the potential implications of inherited epigenetic variation for current theories of inheritance and evolutionary change?

Traditional QTL mapping approaches inadequately capture the complexity of gene networks. The authors show how functional mapping — a general statistical mapping framework — can provide a useful quantitative and testable framework for assessing the interplay between gene actions or interactions during development.

The patentability of genes is a controversial issue. As a partial remedy, many countries have exemptions from patent liability for non-commercial research. However, these exemptions are themselves problematic. The authors examine solutions to the problem and advocate the abolition of gene patents.