BioBriefs.

The article discusses several research studies related to bioscience. A set of footprints, apparently made by a partially submerged dinosaur as it pushed itself across the bottom of a lake, has provided the first evidence of swimming by the carnivorous dinosaurs, Theropoda. The footprints were found in Lower Jurassic rocks at Rocky Hill, Connecticut, where other footprints by herbivorous dinosaurs were found recently. Researcher Donald D. Brown and colleagues announced recently that the genetic machinery of bacteria and that of higher organisms may not be as similar as cell biologists thought. Working with a gene from the frog Xenopus, the researchers discovered that the gene was controlled by a sequence of DNA located not at the ends of the gene, as in bacteria, but in the middle.