News & Views

During meiosis, crossovers are regulated such that each pair of chromosomes has at least one crossover and multiple crossovers are evenly spaced. A new study leads to surprising insights regarding the timing of crossover regulation through the analysis of two genes involved in synaptonemal complex elongation.

Cranial neural crest cell migration is a prerequisite for normal craniofacial morphogenesis in animals. A new study shows that the movement of a specific subset of cranial neural crest cells is exquisitely sensitive to concentrations of a microRNA that targets platelet-derived growth factor receptor alpha mRNA.

Plasma lipoprotein concentrations are associated with risk of coronary artery disease, a leading cause of mortality and morbidity worldwide. Three new genome-wide association studies of thousands of individuals now identify seven genes or loci contributing to lipid concentrations and confirm a number of previously reported associations.

Many organisms have an amazing capacity to adapt to conditions of low oxygen, but the cellular mechanisms of this are poorly understood. A new study in mice has unveiled a molecular trigger that initiates a cascade of events to reprogram cellular oxygen requirements.

Rapid changes in mitochondrial DNA allele frequency between generations have been explained by an 'mtDNA bottleneck' in the germ line, and it has recently been proposed that mtDNA aggregates, or nucleoids, drive such a bottleneck. Now, a new study finds a sharp reduction in mtDNA content in the germ line and suggests that such reduction alone may account for the bottleneck effect.

The discovery of new risk variants for systemic lupus erythematosis (SLE), particularly around lymphocyte signaling pathways and integrins involved in clearing complement, provides fresh insights into this common human autoimmune disease. Understanding the role of the variants in disease pathophysiology and translating these findings into new therapies present major and urgent challenges to medical scientists.

Aberrant meiotic recombination can result in disease-causing chromosome microdeletions or microduplications. A new study of several disease-associated recombination hot spots in male germ cells shows that some genomic rearrangements, particularly microduplications, are significantly underdiagnosed.

Breast tumors with deficiency in DNA double-strand break repair might be expected to show aneuploidy. A new study shows that microdeletions in PTEN, resulting in complete loss of PTEN protein, are signature lesions in these cancers, particularly those arising in BRCA1-mutation carriers.

Accurate measurements of genomic copy number polymorphisms are required to define their medical relevance, but obtaining such measurements for multiallelic copy number variants has been challenging. A copy-number study of psoriasis now sets some useful precedents for a maturing field.

Primary cilia and planar cell polarity (PCP) proteins both contribute to cell polarization, but their relationship is unclear. A new study shows that, in the organ of Corti, primary cilia are required for morphological polarization of sensory hair cells and function downstream of the PCP signaling proteins.

This is an issue edsumm for 1422. Identification of the Palaeocene/Eocene thermal maximum in a marine sedimentary sequence shows that sea surface temperatures near the North Pole increased from roughly 18 degrees Celsius to over 23 degrees Celsius — such warm values imply the absence of ice and thus exclude the influence of ice-albedo feedbacks on this Arctic warming.

Lipoprotein lipase, the enzyme that hydrolyzes fatty acids from triglycerides carried by circulating lipoproteins, resides on the surface of the capillary endothelium. Analysis of a hypertriglyceridemic mutant mouse has now identified a protein, LMF1, that is critical for the transport of active lipoprotein lipase through the secretory pathway.

This is an issue edsumm for 1421. Identification of the Palaeocene/Eocene thermal maximum in a marine sedimentary sequence shows that sea surface temperatures near the North Pole increased from roughly 18 degrees Celsius to over 23 degrees Celsius — such warm values imply the absence of ice and thus exclude the influence of ice-albedo feedbacks on this Arctic warming.

Dramatically different mutant phenotypes usually reflect mutations in different genes, but this is not necessarily so, especially when microRNA regulation is involved. A beautiful example of this now comes from the discovery of the maize microRNA tasselseed4 and its target ids1/Tasselseed6, which uncovers a new facet in the control of inflorescence branching and sex determination in flowers.