Patterns in evolution
Although genome sequencing is increasingly routine for humans, it remains much less common in most other species, and only a small portion of the diversity of life is represented in genomic databases. In this issue, three papers take steps to redress the balance, exploring uncharted branches of vertebrate evolution. In one paper, Guojie Zhang and colleagues from the Bird 10,000 Genomes Project compare 363 genomes representing more than 90% of avian families, including 267 newly sequenced bird species. In another paper, Elinor Karlsson and her colleagues in the Zoonomia Project describe their analysis of 240 genomes representing more than 80% of placental mammal families, including 122 newly sequenced species. To analyse these massive data sets, both teams used new software called Progressive Cactus, which is described by Benedict Paten and co-workers in the third paper. The software can align thousands of genomes spanning hundreds of millions of years of evolution by reconstructing ancestral genomes using cactus graphs. The cover image reflects this process, using stylized mathematical graphs to highlight the software used and create constellations of some species sequenced in this week’s issue.