Network biology

Noise can induce bimodality in positive transcriptional feedback loops without bistability To, T.-L. & Maheshri, N. Science 327, 1142–1145 (2010)

Traditional models of transcription assume that bimodal patterns of gene expression result from cooperative interactions between transcription factors and their binding sites. Studying a synthetic positive-feedback circuit in budding yeast, the authors show that bimodality can also occur by non-cooperative binding at multiple binding sites, provided that a transcription factor is short-lived and has noisy expression — conditions that are widespread.

Disease susceptibility

The lta4h locus modulates susceptibility to mycobacterial infection in zebrafish and humans Tobin, D. M. et al. Cell 140, 717–730

Genome-wide analysis of the host intracellular network that regulates survival of Mycobacterium tuberculosis Kumar, D. et al. Cell 140, 731–743 (2010)

Two studies provide insights into genetic susceptibility to Mycobacterium tuberculosis. In a forward genetic screen for loci that confer susceptibility to Mycobacterium marinum infection in zebrafish, Tobin et al. identified leukotriene A4 hydrolase (lta4h). They also showed that functional human LTA4H polymorphisms are associated with disease protection. Kumar et al. used a genome-wide small interfering RNA screen to find human factors that regulate M. tuberculosis load in infected macrophages. These factors varied according to the genotype and phenotype of M. tuberculosis, and those that regulate load independently of genotype or phenotype were mostly involved in autophagy.

Evo–devo

Changes in Hox genes' structure and function during the evolution of the squamate body plan Di-Poï, N. et al. Nature 464, 99–103 (2010)

How have vertebrate body plans diversified given the constraint of the strict colinearity of Hox genes? These authors show that the Hox clusters of lizards and snakes, unlike other reptiles, contain numerous transposable elements and suggest that this invasion facilitated important changes in both protein coding and regulatory sequences. In line with this theory, they document differences in posterior Hox gene expression and function between snakes and lizards that may have allowed the elongation of the snake body plan without breaching colinearity.

Human genetic variation

Accurate detection and genotyping of SNPs utilizing population sequencing data Bansal, V. et al. Genome Res. 11 Feb 2010 (doi: 10.1101/gr.100040.109)

This paper describes a method for increasing the accuracy of human SNP characterization by using deep sequencing data from populations. In contrast to methods that rely on sequence information from individuals, the new method compares information for a potential SNP across multiple individuals, which decreases false positives caused by systematic sequencing errors. The authors tested their method by sequencing a 200-kb region of the human genome in 48 people and demonstrated high levels of accuracy compared with existing methods.