In a discovery that rips up the rulebook of genetics, researchers in France have shown that RNA, rather than its more famous cousin DNA, might be able to ferry information from one generation of mice to the next. DNA has long been credited with the job of passing traits from parent to child. Sperm and egg deliver that DNA to the embryo, where it ultimately decides much of our looks and personality.
The new study in Nature thrusts RNA, DNA’s sidekick, into the limelight. It suggests that sperm and eggs of mammals, perhaps including humans, can carry a cargo of RNA molecules into the embryo – and that these can change that generation and subsequent ones. “It’s a very exciting possibility,” says Emma Whitelaw who studies patterns of inheritance at Queensland Institute of Medical Research in Brisbane, Australia. “DNA is certainly not all you inherit from your parents.”