The evolutionary trajectory of the red algae Cyanidiales is shown from top to bottom. Rossini et al. investigated genetic changes that took place before and after the Cambrian explosion 541 million years ago, and found that Cyanidiales obtained 1% of their genes during this time by horizontal transfer. Many of these genes allowed Cyanidiales to adapt to extreme environments, such as genes related to the detoxification of heavy metals including mercury and arsenic (represented by green arrows). Some of the lineages of Cyanidiales that were sequenced by Rossoni et al. are shown in the bottom panels: two of these have the same taxonomic name despite having diverged from one another millions of years ago. Image credit: Andreas Weber (left panel), Debashish Bhattacharya (two middle panels), and Shin-ya Miyagishima (right panel).