The Role of DNA Methylation in Genome Defense in Cnidaria and Other Invertebrates

Ying, Hua, Hayward, David C., Klimovich, Alexander, Bosch, Thomas C.U., Baldassarre, Laura, Neeman, Teresa, Foret, Sylvain, Huttley, Gavin, Reitzel, Adam M., Fraune, Sebastian, Ball, Eldon E., and Miller, David (2022) The Role of DNA Methylation in Genome Defense in Cnidaria and Other Invertebrates. Molecular Biology and Evolution, 39 (2). msac018.

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Considerable attention has recently been focused on the potential involvement of DNA methylation in regulating gene expression in cnidarians. Much of this work has been centered on corals, in the context of changes in methylation perhaps facilitating adaptation to higher seawater temperatures and other stressful conditions. Although first proposed more than 30 years ago, the possibility that DNA methylation systems function in protecting animal genomes against the harmful effects of transposon activity has largely been ignored since that time. Here, we show that transposons are specifically targeted by the DNA methylation system in cnidarians, and that the youngest transposons (i.e., those most likely to be active) are most highly methylated. Transposons in longer and highly active genes were preferentially methylated and, as transposons aged, methylation levels declined, reducing the potentially harmful side effects of CpG methylation. In Cnidaria and a range of other invertebrates, correlation between the overall extent of methylation and transposon content was strongly supported. Present transposon burden is the dominant factor in determining overall level of genomic methylation in a range of animals that diverged in or before the early Cambrian, suggesting that genome defense represents the ancestral role of CpG methylation.

Item ID: 74626
Item Type: Article (Research - C1)
ISSN: 1537-1719
Keywords: Cnidaria, Coral, DNA methylation, Epigenetics, Genome defense, Transposons
Copyright Information: © The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Date Deposited: 30 Nov 2022 01:49
FoR Codes: 31 BIOLOGICAL SCIENCES > 3105 Genetics > 310509 Genomics @ 40%
31 BIOLOGICAL SCIENCES > 3101 Biochemistry and cell biology > 310199 Biochemistry and cell biology not elsewhere classified @ 60%
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