PTC124 sticks to ribosomes — the cells’ protein factories — and prompts them to interpret a premature stop codon as a normal codon. Instead of aborting assembly of the protein, the ribosome inserts a protein building block — an amino acid — and continues making a complete protein chain until it encounters the normal termination codon, which the ribosome correctly interprets as a stop. read story
When it comes to getting a start in this world, flies don’t dillydally. After fertilization, a one-celled egg in the fruit fly (Drosophila melanogaster) takes but three hours to develop into a hollow oval containing some 8,000 cells. Ten minutes later, sheets of cells from the edge of the sphere stream into the center, establishing what will become Drosophila’s internal tissues and organs. In less than a day, the tiny fly larva works its way out from its eggshell. read in full issue (pdf)
Scientists have known for some time that certain genes affect the way our shapes ultimately shape up–how we develop physically. Now, researchers have pinpointed two families of genes suspected of playing a central role in the “master Plan” of how vertebrate skeletons are sculpted. read in full issue (pdf)
The first eyewitness to the birth of a new species may be a University of Arizona graduate student. Her new findings could help biologists identify and understand the precise genetic changes that lead one species to evolve into two separate species. read story
Rock pocket mice are common denizens of the Sonoran desert regions around Tucson, but you’ll probably never see one in the wild. The small rodents are strictly nocturnal, finding refuge from the daytime desert heat in their underground burrows. By night, they gather seeds, their only source of food and water, and do their best to elude owls, their main predators. Now, these inconspicuous animals may have gained some celebrity as a textbook example of adaptation by natural selection, thanks to a team of University of Arizona evolutionary biologists. read story
Living cells have “molecular paper shredders” that purge outdated genetic instructions. The subcellular structures were discovered by Ujwal Sheth, a University of Arizona Ph.D. candidate in molecular and cellular biology, and her advisor, Regents’ Professor Roy Parker. The pair reported their findings this week in the journal Science. read story
Some things just never seem to change. The adage holds true for an unlikely subject — the genetic material of bacteria living inside aphids, those squishy green insects you can’t keep out of your garden — according to a pair of University of Arizona evolutionary biologists. read story
Size matters–at least for worm sperm. For tiny soil nematodes, big sperm have the edge over smaller sperm in fertilizing a mate’s eggs, according to University of Arizona biologists Craig LaMunyon and Samuel Ward. read story