Abstract Detail

A Botanist at the Extreme: Honoring the great contributions of Dr. Vicki A. Funk

Knope, Matthew [1].

Explosive adaptive radiation of Bidens (Compositae) across the most isolated archipelagos in the world.

In the native Hawaiian flora, we often observe high species richness and extreme eco-morphological differentiation, despite limited genetic differentiation; a situation I refer to as the “Hawaiian plant paradox”. The endemic Hawaiian species in the genus Bidens are considered to be among the best examples of adaptive radiation in the Hawaiian flora, as they have radiated into almost every habitat type available in Hawaiʻi, and the 19 endemic Hawaiian species exhibit greater eco-morphological variation than the remaining ~200 species in the genus found across five continents. To address this apparent paradox, we set out to build genomic resources to attempt to resolve the phylogeny, test the progression rule in Hawaiʻi (dispersal and speciation from older to younger islands, as they become available), determine their colonization history throughout the other extremely remote archipelagos of Polynesia, and ultimately to work on the functional genomics of trait evolution. To do so, we embarked on a 15-year collecting effort led by Vicki A. Funk, vouchered and extracted DNA for 91 species, and then utilized traditional Sanger sequencing, Illumina Hi Seq shotgun sequencing, and PacBio SMRT cell long-read high-fidelity technology to generate a high-quality reference genome. We found extremely low genetic divergence among all of the Hawaiian taxa, but a BEAST analysis of the concatenated whole plastome and nuclear ribosomal complex generates a fully bifurcating tree for the Hawaiian taxa, with generally high statistical confidence at nodes. However, considerable nuclear-plastome tree topology conflict exists, indicating a role of hybridization and/or incomplete lineage sorting. Further, we found evidence for recent Central/South American ancestry of the Pacific radiation (with Polynesian crown group diversification starting ~1.63 Mya) with intital long-distance dispersal to Hawaiʻi and the Marquesas, and then from the Marquesas to the Society and Austral Islands. Young plant lineages on island archipelagos pose challenges for phylogenetic and biogeographic reconstruction, but given these new results, we are cautiously optimistic that it is now possible to reconstruct the evolutionary history of recent plant adaptive radiations using phylogenomic approaches and we expect that we are at the beginning of a new frontier in terms of understanding how island plant biodiversity is generated. In addition, I will also present ongoing work with Kenneth R. Wood, describing a new species of waterfall associated Bidens endemic the “Blue Hole” in the island interior of Kauaʻi, directly beneath Mount Waiʻaleʻale, one of the wettest spots on Earth.

1 - University of Hawaiʻi at Hilo, Biology, 200 W. Kawili St., Hilo, HI, 96746, USA

long distance dispersal
seed dispersal
Floral traits
new species

Presentation Type: Symposium Presentation
Number: S4007
Abstract ID:366
Candidate for Awards:None

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