Jeramiah J. Smith

Abstract Promoter-proximal pausing of RNA polymerase (Pol) II is a key regulatory step during transcription. Despite the central role of pausing in gene regulation, we do not understand the evolutionary processes that led to the emergence of Pol II pausing or its transition to a rate-limiting step actively controlled by transcription factors. Here, we analyzed transcription in species across the tree of life.

Abstract As the only surviving lineages of jawless fishes, hagfishes and lampreys provide a critical window into early vertebrate evolution1–3. Here, we investigate the complex history, timing, and functional role of genome-wide duplications4–7 and programmed DNA elimination8,9 in vertebrates in the light of a chromosome-scale genome sequence for the brown hagfish Eptatretus atami.

Marie Delattre, a biologist at the École Normale Supérieure de Lyon, has studied the nematode Mesorhabditis belari for nearly a decade now. The microscopic worm first caught her attention for its unconventional approach to reproduction, where only a small fraction of offspring keep their male parent’s DNA.1 But more recently, she was looking at Mesorhabditis embryos under a microscope and noticed something else that was odd: in some embryos, the DNA was shattered into small fragments.