Abstract

Genome sequencing has demonstrated that besides frequent small-scale duplications, large-scale duplication events such as whole genome duplications (WGDs) are found on many branches of the evolutionary tree of life. Especially in the plant lineage, there is evidence for recurrent WGDs, and the ancestor of all angiosperms was in fact most likely a polyploid species. The number of WGDs found in sequenced plant genomes allows us to investigate questions about the roles of WGDs that were hitherto impossible to address. An intriguing observation is that many plant WGDs seem associated with periods of increased environmental stress and/or fluctuations, a trend that is evident for both present-day polyploids and palaeopolyploids formed around the Cretaceous–Palaeogene (K–Pg) extinction at 66 Ma. Here, we revisit the WGDs in plants that mark the K–Pg boundary, and discuss some specific examples of biological innovations and/or diversifications that may be linked to these WGDs. We review evidence for the processes that could have contributed to increased polyploid establishment at the K–Pg boundary, and discuss the implications on subsequent plant evolution in the Cenozoic.

Highlights

  • Flowering plants typically have large genome sizes and contain many genes, the majority of which evolved during the past 250–300 Myr through gene duplication [1]

  • It is commonly accepted that one whole genome duplications (WGDs) occurred in the ancestor of all seed plants, and an extra one in the ancestor of all flowering plants, so that every extant angiosperm is a palaeopolyploid containing the remnants of at least two WGDs [5]

  • A hexaploidy event pre-dates the origin of all core eudicots, which make up approximately 75% of extant angiosperm diversity [6,7,8], whereas traces of a WGD at the base of the monocots suggest a WGD shared by most, if not all, monocots [9]

Read more

Summary

Introduction

Flowering plants typically have large genome sizes and contain many genes, the majority of which evolved during the past 250–300 Myr through gene duplication [1]. It is commonly accepted that one WGD occurred in the ancestor of all seed plants, and an extra one in the ancestor of all flowering plants, so that every extant angiosperm is a palaeopolyploid containing the remnants of at least two WGDs [5]. We have an in-depth look at this wave of WGDs associated with the K–Pg boundary, many of which pre-date lineage diversifications that resulted in some of the largest and arguably most successful present-day plant families, often characterized by particular biological innovations. License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited

A burst of genome duplications at the Cretaceous –Palaeogene boundary
Conclusion
Findings
80. Osborn TC et al 2003 Understanding mechanisms

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 call

Disclaimer: 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.