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.
Highlights
Whole genome duplications (WGDs) have been prevalent during the evolutionary history of flowering plants, and have even been linked to their origin as well as their fast rise to ecological dominance [1,2,3]
Based on age distributions of paralogs inferred from synonymous substitutions per synonymous site, or so-called KS distributions [29], a distinct peak with a median KS of ~0.8 was identified for E. natalensis (Fig 1), a clear signature of an ancient WGD event
G. biloba showed a similar KS distribution, and contained a peak at a KS of ~0.8 (Fig 1). This distribution is consistent with data reporting the presence of a WGD event in the evolutionary history of ginkgo [13]
Summary
Whole genome duplications (WGDs) have been prevalent during the evolutionary history of flowering plants, and have even been linked to their origin as well as their fast rise to ecological dominance [1,2,3]. Far fewer gymnosperm species exist today compared to the angiosperms, and as such many lineages containing evidence for WGD events could have been lost, polyploidy events, ancient or more recent, in these seed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
