A comprehensive genomic history of extinct and living elephants
Program in Bioinformatics and Integrative Biology
Bioinformatics | Computational Biology | Ecology and Evolutionary Biology | Genetic Phenomena | Genomics | Paleobiology | Paleontology
Elephantids are the world's most iconic megafaunal family, yet there is no comprehensive genomic assessment of their relationships. We report a total of 14 genomes, including 2 from the American mastodon, which is an extinct elephantid relative, and 12 spanning all three extant and three extinct elephantid species including an approximately 120,000-y-old straight-tusked elephant, a Columbian mammoth, and woolly mammoths. Earlier genetic studies modeled elephantid evolution via simple bifurcating trees, but here we show that interspecies hybridization has been a recurrent feature of elephantid evolution. We found that the genetic makeup of the straight-tusked elephant, previously placed as a sister group to African forest elephants based on lower coverage data, in fact comprises three major components. Most of the straight-tusked elephant's ancestry derives from a lineage related to the ancestor of African elephants while its remaining ancestry consists of a large contribution from a lineage related to forest elephants and another related to mammoths. Columbian and woolly mammoths also showed evidence of interbreeding, likely following a latitudinal cline across North America. While hybridization events have shaped elephantid history in profound ways, isolation also appears to have played an important role. Our data reveal nearly complete isolation between the ancestors of the African forest and savanna elephants for approximately 500,000 y, providing compelling justification for the conservation of forest and savanna elephants as separate species.
admixture, elephantid evolution, mammoth, paleogenomics, species divergence
DOI of Published Version
Proc Natl Acad Sci U S A. 2018 Mar 13;115(11):E2566-E2574. doi: 10.1073/pnas.1720554115. Epub 2018 Feb 26. Link to article on publisher's site
Proceedings of the National Academy of Sciences of the United States of America
Palkopoulou, Eleftheria; Karlsson, Elinor K.; and Reich, David, "A comprehensive genomic history of extinct and living elephants" (2018). Program in Bioinformatics and Integrative Biology Publications and Presentations. 144.