Scientists studying the kangaroo genome have cast doubt on the credentials of a gene thought to be crucial to the process of inactivating one sex chromosome in women. The finding challenges a whole field of research that has developed around the XIST gene since its discovery in the early 1990s. Scientists had expected that the gene – which was thought to direct the switching off of a surplus X chromosome during embryonic development – would inform our understanding of how genes are controlled in normal development, and how control goes awry in genetic diseases such as cancer. The sophisticated genetic...