In a new book, Eclipsed Horizons: Unveiling the Dark Genome, Sudhakaran Prabakaran looks at how the vast and once-overlooked landscape of the ‘dark genome' may explain evolution's greatest leaps. Over the past two decades, molecular biology has undergone a profound shift. Non-coding DNA is now recognised as a major regulator of gene expression. In the second of a two-part series, we tap into this evolving understanding of the 'dark genome'.