Genes & Cells

Quick hit
Smoking can cause immediate damage to DNA, a new study warns. Within minutes of puffing a cigarette, a chemical in smoke called a polycyclic aromatic hydrocarbon, or PAH, gets converted into a DNA-damaging form known as a PAH diol epoxide in smokers’ blood, researchers from the University of Minnesota discovered. “The results reported here should serve as a stark warning to those who are considering starting to smoke cigarettes: PAH diol epoxide formation occurs immediately and is not a theoretical long-term effect,” the team writes in the Feb. 18 Chemical Research in Toxicology. —Tina Hesman Saey

Grapevine genetics
A genetic analysis of grapes suggests that most varieties are very close relatives. Grapes are usually cultivated by taking cuttings from old vines, which allows beneficial mutations that crop up in single plants to be maintained for centuries, but also discourages breeders from developing new strains that could fight diseases more effectively or improve other qualities, an international team of researchers reports online January 18 in the Proceedings of the National Academy of Sciences. —Tina Hesman Saey

Clocks keep ticking without gears
Biological clocks that govern daily rhythms can keep ticking even without what scientists had thought to be essential clockworks. These biological, or circadian, clocks help determine sleep patterns and control the timing of many other body functions. Scientists have shown that rhythmic copying of DNA instructions into RNA — a process called transcription — is what drives the clocks. But human red blood cells and a type of algae called Ostreococcus tauri have circadian clocks that don’t include transcription as gears in their mechanisms, report John O’Neill of the University of Cambridge in England and colleagues in two studies that both appear in the Jan. 27 Nature. —Tina Hesman Saey

First crustacean genome
Water fleas are the first crustaceans to have their complete genetic blueprints deciphered. The species of water flea called Daphnia pulex has at least 30,907 genes — thousands more than humans — an international team of researchers reports in the Feb. 4 Science. The large number of genes is due to duplication of genes or groups of genes, about a third of which are found in no other organism. Carbon-copying genes may allow water fleas to adapt rapidly to changing environmental conditions. —Tina Hesman Saey