Journal Article

Independent Mammalian Genome Contractions Following the KT Boundary

Mina Rho, Mo Zhou, Xiang Gao, Sun Kim, Haixu Tang and Michael Lynch

in Genome Biology and Evolution

Published on behalf of Society for Molecular Biology and Evolution

Volume 1, issue , pages 2-12
Published in print January 2009 |
Published online May 2009 | e-ISSN: 1759-6653 | DOI:

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Although it is generally accepted that major changes in the earth's history are significant drivers of phylogenetic diversification and extinction, such episodes may also have long-lasting effects on genomic architecture. Here we show that widespread reductions in genome size have occurred in multiple lineages of mammals subsequent to the Cretaceous–Tertiary (KT) boundary, whereas there is no evidence for such changes in other vertebrate, invertebrate, or land plant lineages. Although the mechanisms remain unclear, such shifts in mammalian genome evolution may be a consequence of an increase in the efficiency of selection against excess DNA resulting from post-KT population size expansions. Independent historical changes in genome architecture in diverse lineages raise a significant challenge to the idea that genome size is finely tuned to achieve adaptive phenotypic modifications and suggest that attempts to use phylogenetic analysis to infer ancestral genome sizes may be problematical.

Keywords: genome evolution; genome size; KT boundary; mammalian evolution; mobile elements; pseudogenes; retrotransposons

Journal Article.  7049 words.  Illustrated.

Subjects: Bioinformatics and Computational Biology ; Evolutionary Biology ; Genetics and Genomics