Cover image

A “classic model” describes the mechanism of transcription initiation shared by most eukaryotic organisms but some yeasts use a distinct mechanism that can be described as the “scanning model.” In this issue, it is reported when and how this mechanism of transcription initiation originated and diversified during the evolution of yeasts. The cover art illustrates the diversification of transcription initiation mechanisms from their common ancestor (represented by the DNA double helix–shaped tree). The blue and white tree branches with “bubbles” indicate where the DNA double helix is unwound and transcription is initiated. The red and purple birds in the tree represent the two distinct mechanisms of transcription initiation. The oval shapes underneath the tree represent yeasts. (Cover illustration concept by Zhenguo Lin. Artwork by Qiushi Wang, https://www.zcool.com.cn/u/176004/. © 2021 Saint Louis University. [For details, see Lu and Lin, pp. 51–63.])