Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution

TLDR

The sea lamprey, a vertebrate that diverged from humans about 500 million years ago, offers a unique genomic perspective on the ancestry and fundamental biology of vertebrate genomes. The study presents the first lamprey whole‑genome sequence and assembly. The authors assembled the lamprey genome, overcoming challenges posed by its high repetitive and GC‑rich content and limited related reference data. Analyses reveal two whole‑genome duplications preceding lamprey–gnathostome divergence, identify key vertebrate evolutionary events such as the emergence of myelin proteins and appendage development, and establish the lamprey genome as a valuable resource for reconstructing vertebrate origins.

Abstract

Jeramiah Smith, Weiming Li and colleagues report the whole-genome sequence of the sea lamprey, Petromyzon marinus, representing a vertebrate lineage diverged from humans ~500 million years ago. Their analyses define key evolutionary events in vertebrate lineages and provide evidence for two whole-genome duplication events occurring before the divergence of the ancestral lamprey and jawed vertebrate (gnathostome) lineages. Lampreys are representatives of an ancient vertebrate lineage that diverged from our own ∼500 million years ago. By virtue of this deeply shared ancestry, the sea lamprey (P. marinus) genome is uniquely poised to provide insight into the ancestry of vertebrate genomes and the underlying principles of vertebrate biology. Here, we present the first lamprey whole-genome sequence and assembly. We note challenges faced owing to its high content of repetitive elements and GC bases, as well as the absence of broad-scale sequence information from closely related species. Analyses of the assembly indicate that two whole-genome duplications likely occurred before the divergence of ancestral lamprey and gnathostome lineages. Moreover, the results help define key evolutionary events within vertebrate lineages, including the origin of myelin-associated proteins and the development of appendages. The lamprey genome provides an important resource for reconstructing vertebrate origins and the evolutionary events that have shaped the genomes of extant organisms.