This Week in Science: May 30, 2008

The Parkinson's Institute and Clinical Center and 23andMe will be starting a study to see if Parkinson's disease can be assessed via the Web. The company will be designing and adapting a questionnaire to be filled out online by the patients, to see if their health and health history can be accurately gauged this way. The participants will also be giving saliva samples to 23andMe to be sequenced and then matched to their online responses. "We want to build this engine basically to be able to power genomewide association studies," says Linda Avey, whose company also plans to use this strategy for other diseases.

DNA from Paleo-Eskimos, people who lived in the northern parts of Alaska, Canada, and Greenland about 4500 years ago, shows that they are neither descendants of the Asian people who crossed the Bering Strait and became Native Americans, nor are they the ancestors of modern Eskimos. By sequencing the mitochondrial DNA of a clump of hair from a Paleo-Eskimo in Greenland (the hair was frozen in permafrost) and comparing it to Neo-Eskimos, who arrived 1000 years ago, and to modern Native Americans, the researchers saw it contained a rare marker, D2a1, which is not present in any of the other groups, nor in the Europeans that collected the sample. This marker is similar to D2a1a, found in Aleuts and Siberian Eskimos of the Commander Islands, suggesting that the Paleo-Eskimos came from that region.

Researchers led by Olivier Voinnet studied Arabidopsis mutants that have defective miRNA action. From this, they report that the miRNA and siRNA-mediated silencing in plants is separate from the endonucleolytic cleavage. Translational repression is by AGO1 and AGO10, along with katanin, a microtubule-severing enzyme, and VCS/Ge1, a decapping component.