Reviews & Analysis

A massive study of expressed-sequence tags from both free-living and parasitic nematodes identifies tens of thousands of genes not present in Caenorhabditis elegans. Half of these are unique to nematodes and should provide new insights into the lifestyles of parasitic nematodes.

Protein tyrosine phosphatases (PTPs) have diverse roles as negative regulators of stimulatory signaling cascades and are widely recognized as key to maintaining immune cellular homeostasis. Recent data implicating the PTP Lyp in susceptibility to four autoimmune diseases attests to the biological importance of PTP immune regulatory roles and to the etiologic relatedness of different autoimmune conditions.

As geneticists begin to identify gene variants associated with common diseases and responses to treatment, it is increasingly important to determine whether these variants have consistent effects across different 'racial' or 'ethnic' groups. Until recently, too little was known about either disease genetics or pharmacogenetics to make a detailed assessment. Now, a new study reviewing 43 disease-associated gene variants suggests that the effects of gene variants may be largely consistent across different 'racial' or 'ethnic' groups.

In eukaryotes, RNA silencing suppresses gene expression through sequence-specific interactions involving endogenous small RNAs. Although our understanding of the diversity, biogenesis and function of these regulatory RNAs is growing rapidly, their evolutionary origin is not well understood. Now, a new study of plants uncovers an important role for inverted duplication of small RNA target genes in the origin of new regulatory RNAs.

Truncating and missense mutations in BUB1B, encoding the mitotic spindle checkpoint protein BUBR1, have been identified in individuals with mosaic variegated aneuploidy. This finding supports the idea that there is a genetic basis for aneuploidy in cancers.

Transcriptional silencing in fission yeast requires several core components of the RNA interference machinery. A new study suggests that the recently discovered RNA-induced initiation of transcriptional gene silencing complex binds stably to silent chromatin, where it recruits short interfering RNAs and destroys nascent RNA molecules in cis.

One challenge in modern biology is to understand the detailed genetic basis of variation for quantitative traits, including complex behaviors. A new study shows that historical recombination in outbred strains combined with functional complementation tests can identify pleiotropic genes with small effects on naturally occurring variation for anxiety-related behaviors in mice.

Defects in the breakdown of gangliosides are associated with a class of disorders known as lysosomal storage diseases. Now, a defect in the synthesis of gangliosides, glycolipids that contain sialic acid and are abundant in the brain, has been shown to underlie an inherited form of epilepsy.

A new study shows that Fanconi anemia complementation group B is caused by mutations in a previously uncharacterized gene located on the X chromosome. Its unique chromosomal localization identifies FANCB as a potential weak link in a key DNA-repair and tumor-suppressor pathway.

MicroRNAs are important in the development of worms, flies and plants. A new study shows how the temporal and spatial expression patterns of such RNAs can be determined in mouse embryos, providing insights into the emerging role of microRNAs in Hox gene regulation.

Many genes and genetic mechanisms contributed to the evolution of humans from a common primate ancestor. Emergence of the ape brain was apparently facilitated by a retrotransposed gene duplicate that acquired brain-specific expression and functions affecting the neurotransmitter glutamate.

A new study shows that poly(ADP-ribosyl)ation of CTCF regulates its activity as a transcriptional insulator without altering its DNA binding properties. This mechanism provides cells with the flexibility to regulate gene expression without altering fundamental epigenetic programs.

Studies of inherited cancer syndromes have implicated numerous signaling pathways in colorectal carcinogenesis, but the relationship between these signaling pathways remains poorly understood. Now, a new mouse model of juvenile polyposis syndrome identifies a molecular mechanism for clonal epithelial cell expansion and links several pathways with an established role in polyposis.

Two papers report that large-scale copy-number variations, ranging in size from 100 kb to 2 Mb, are distributed widely throughout the human genome, and that a high proportion of them encompass known genes. This unexpected level of genome variation has implications for our view of human genetic diversity and phenotypic variation.