Genes & Cells

Genes for butterfly wings and maintaining maleness, plus turtles meet their lizard relatives and more in this week’s news

Centenarian genetics study retracted
Scientists still can’t predict who will live to be 100. A study published online in Science last year claimed to have found a genetic signature of longevity, but other researchers pointed to technical problems in the data. Now, the original researchers at Boston University and colleagues have removed the suspect data and reanalyzed the results. After a new review, Science has determined that the corrected findings are not strong enough for publication and has asked the team to retract the study. The journal says there was no misconduct, and the researchers say they will seek publication elsewhere. The retraction appears in the July 22 Science. —Tina Hesman Saey


Butterfly splendor set by single gene
Heliconius butterflies paint their wings in many different patterns to mimic poisonous species, but they use only one genetic paintbrush to do it. A single gene called optix controls all of the red color patterns on the wings of Heliconius butterflies, researchers led by Robert Reed at the University of California, Irvine report online July 21 in Science. Various color patterns are probably due to changes in where and when the gene is turned on and off, rather than alterations of the gene itself. —Tina Hesman Saey

Being male is high-maintenance
Boys will be boys, but only if they have a gene that prevents them from turning into girls, a new study in mice suggests. A gene called DMRT1 prevents cells in the testes from being reprogrammed into ovary cells, researchers from the University of Minnesota and Washington State University in Pullman report online July 20 in Nature. Removing the gene from male mice caused cells in the testes to transform into estrogen-producing cells, even in adult males. The findings could help explain some disorders in humans and shed light on how some adult fish switch sexes. —Tina Hesman Saey

Bacterial slingshots
Fishtailing helps bacteria get around easier, scientists have learned after watching slow-motion movies of Pseudomonas aeruginosa bacteria. The microbes use hairlike appendages called type IV pili to crawl along surfaces. Suddenly releasing one of the pili causes a “slingshot” motion that whips the cell into a new position, researchers led by Gerard Wong at the UCLA found. The fishtail motion helps liquefy surrounding fluids, reducing viscosity by 50 to 80 percent, the researchers report online July 18 in the Proceedings of the National Academy of Sciences. Figuring out how bacteria move may help scientists learn to fight them better. —Tina Hesman Saey

Turtles are lizards
Turtles’ origins have been shrouded in mystery. Now, a new study comparing small snippets of genetic material called microRNAs finds that turtles’ closest relatives are lizards. Previous molecular studies had grouped turtles with crocodiles and birds, but researchers led by Kevin Peterson of Dartmouth College found that turtles and lizards share four groups of microRNAs that aren’t found in any other animals. The researchers propose in a paper published online July 20 in Biology Letters that turtles and lizards be classified in a new group called Ankylopoda. —Tina Hesman Saey

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