title: The sea lamprey meiotic map improves resolution of ancient vertebrate genome duplications.
abstract: It is generally accepted that many genes present in vertebrate genomes owe their origin to two whole-genome duplications that occurred deep in the ancestry of the vertebrate lineage. However, details regarding the timing and outcome of these duplications are not well resolved. We present high-density meiotic and comparative genomic maps for the sea lamprey (Petromyzon marinus), a representative of an ancient lineage that diverged from all other vertebrates ∼550 million years ago. Linkage analyses yielded a total of 95 linkage groups, similar to the estimated number of germline chromosomes (1n ∼ 99), spanning a total of 5570.25 cM. Comparative mapping data yield strong support for the hypothesis that a single whole-genome duplication occurred in the basal vertebrate lineage, but do not strongly support a hypothetical second event. Rather, these comparative maps reveal several evolutionarily independent segmental duplications occurring over the last 600+ million years of chordate evolution. This refined history of vertebrate genome duplication should permit more precise investigations of vertebrate evolution.
authors.affiliation: Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA.
authors.forename: Jeramiah J
authors.initials: JJ
authors.lastname: Smith
authors.affiliation: Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA.
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Keinath
mesh_terms: D000818:Animals; D002874:Chromosome Mapping / Q000379:methods*; D002875:Chromosomes / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D016678:Genome; D006801:Humans; D008540:Meiosis; D048428:Petromyzon / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D026801:Synteny; D014714:Vertebrates / Q000235:genetics*