Volume 10 Issue 3, March 2009

The recent discovery that most of the eukaryotic genome is transcribed has focused interest on the importance of non-coding transcripts. Long non-coding RNAs are emerging as a class with wide-ranging functions in gene regulation.

Principles and patterns of nucleosome positioning have emerged through recent advances in genome-wide mapping technologies. These patterns have improved understanding of how DNA sequence and protein complexes control nucleosome location and the influence of nucleosome positioning on transcriptional control.

Mutations that affect the extracellular matrix (ECM) cause a range of inherited diseases. As well as exerting effects outside the cell, increasing evidence suggests that misfolded mutant proteins can cause stress inside cells, which contributes to disease pathology.

Mapping genetic variants that cause changes in transcript levels is a new tool that can give insight into the biology of disease risk loci identified by genome-wide association studies; here the potential power and technical challenges of this approach are discussed.

Effective population size and patterns of molecular evolution and variation Brian Charlesworth Effective population size (N_e) is a core concept in population genetics that is necessary for determining the evolutionary role of genetic drift. This Review discusses current understanding of the influences on, and importance of, N_ein different biological situations.

In mammals, errors in synapsis are associated with impaired meiosis, which is male-biased and is associated with reduced fertility. The recent discovery that asynapsed chromosome segments are transcriptionally silenced has provided fresh insight into the connection between asynapsis and meiotic impairment.