Regressive evolution of an effector following a host jump in the Irish potato famine pathogen lineage.

In order to infect a new host species, the pathogen must evolve to enhance infection and transmission in the novel environment. Although we often think of evolution as a process of accumulation, it is also a process of loss. Here, we document an example of regressive evolution of an effector activity in the Irish potato famine pathogen (Phytophthora infestans) lineage, providing evidence that a key sequence motif in the effector PexRD54 has degenerated following a host jump.

Rapidly star-forming galaxies adjacent to quasars at redshifts exceeding 6.

The existence of massive (10 solar masses) elliptical galaxies by redshift z ≈ 4 (refs 1, 2, 3; when the Universe was 1.5 billion years old) necessitates the presence of galaxies with star-formation rates exceeding 100 solar masses per year at z > 6 (corresponding to an age of the Universe of less than 1 billion years). Surveys have discovered hundreds of galaxies at these early cosmic epochs, but their star-formation rates are more than an order of magnitude lower.

Insights into the survival of Chlamydomonas reinhardtii during sulfur starvation based on microarray analysis of gene expression.

Responses of photosynthetic organisms to sulfur starvation include (i) increasing the capacity of the cell for transporting and/or assimilating exogenous sulfate, (ii) restructuring cellular features to conserve sulfur resources, and (iii) modulating metabolic processes and rates of cell growth and division. We used microarray analyses to obtain a genome-level view of changes in mRNA abundances in the green alga Chlamydomonas reinhardtii during sulfur starvation. The work confirms and extends upon previous findings showing that sulfur deprivation elicits changes in levels of transcripts for proteins that help scavenge sulfate and economize on the use of sulfur resources.

Reactive erosive arthritis in chimpanzees.

Diagnosis of diseases of bone, without benefit of soft tissue, in vivo observation, or blood component analysis requires the development of new criteria for diagnosis. Analyzing chimpanzee skeletal populations, applying such criteria (e.g.