Mutations are a fact of life. Darwin gave mutations, which he called natural variation between individuals, a key role to explain the origin of species. The origin and nature of mutations is one of the most fundamental questions of biology, and are a hot topic in origin debates. If mutations are merely a matter of chance, then the alignment of mutations in distinct species that do not reproduce...

PAS (PER-ARNT-SIM) domains are a family of sensor protein domains involved in signal transduction in a wide range of organisms. Recent structural studies have revealed that these domains contain a structurally conserved alpha/beta-fold, whereas almost no conservation is observed at the amino acid sequence level. The photoactive yellow protein, a bacterial light sensor, has been proposed as the ...

The extraordinary impact of Thomas Paine's Common Sense has often been attributed to its style to the simplicity and forcefulness with which Paine expressed ideas that many others before him had expressed. Comparative analysis of Common Sense and other pre-Revolutionary pamphlets suggests that Common Sense was indeed stylistically unique; no other pamphleteer came close to matching Paine's comb...

PAS (PER-ARNT-SIM) domains are a family of sensor protein domains involved in signal transduction in a wide range of organisms. Recent structural studies have revealed that these domains contain a structurally conserved / -fold, whereas almost no conservation is observed at the amino acid sequence level. The photoactive yellow protein, a bacterial light sensor, has been proposed as the PAS stru...