Quite a few new things in this article to shake up out thoughts about early evolution.
https://www.science.org/content/article/giant-viruses-played-key-role-early-life-study-yellowstone-hot-spring-suggests?ut
A study in Yellowstone hot spring suggests
DNA analyses reveal viruses have infected red algae—and spurred evolution—for at least 1.5 billion years.
Giant viruses have amazed biologists since their discovery in 2003. They can be larger than some bacteria, their genomes are big, and they have some characteristics of bacteria and other cellular forms of life. Biologists have found giant viruses in the deep sea and hiding in the genomes of red algae. They also inhabit hot springs.
Lemonade Creek, a very acidic hot spring creek in Yellowstone whose temperatures hover around 44°C. The creek’s floor is covered by a thick green mat that—despite its color—consists of Rhodophyta, or red algae. Researchers took samples from the mat, the adjacent soil, and the space between nearby rocks lying nearby.
… able to piece together most of the genomes of about 25 different types of viruses. They think these reproduce by infecting the red algae. Because hot springs come and go over geological time, the researchers assumed none of the giant viruses would be very old. …Their association with red algae likely dates back 1.5 billion years.
Another surprising discovery: The viral communities on the algal mat, in the soil, and between the rocks were surprisingly different. I would have thought that there would be more exchange between neighboring sites that are sometimes only a few centimeters apart. How and why these communities stay so isolated is another mystery.