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Updated: Feb 23, 2026

G2-seq: A High Throughput Sequencing-based Technique for Identifying Late Replicating Regions of the Genome
Published on: March 22, 2018
Evidence for an ancient whole genome duplication in the cycad lineage
Danielle Roodt1,2, Rolf Lohaus3,4,5, Lieven Sterck3,4,5
1Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private bag X20, Pretoria, South Africa.
Abstract:
Contrary to the many whole genome duplication events recorded for angiosperms (flowering plants), whole genome duplications in gymnosperms (non-flowering seed plants) seem to be much rarer. Although ancient whole genome duplications have been reported for most gymnosperm lineages as well, some are still contested and need to be confirmed. For instance, data for ginkgo, but particularly cycads have remained inconclusive so far, likely due to the quality of the data available and flaws in the analysis. We extracted and sequenced RNA from both the cycad Encephalartos natalensis and Ginkgo biloba. This was followed by transcriptome assembly, after which these data were used to build paralog age distributions. Based on these distributions, we identified remnants of an ancient whole genome duplication in both cycads and ginkgo. The most parsimonious explanation would be that this whole genome duplication event was shared between both species and had occurred prior to their divergence, about 300 million years ago.
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