Abstract Detail



Systematics

Schneider, Adam [1].

Using horizontal gene transfer events to improve divergence time estimation: A case study in the Orobanchaceae.

Horizontal gene transfer (HGT) from autotrophic plants to their heterotrophic parasites has been observed in many lineages of angiosperms, including the Orobanchaceae. These genes can be thought of as "molecular fossils", in that they provide evidence of ancient host-parasite associations. Integrating this data into a phylogenetic framework has the potential to inform our hypotheses about the ecology, biogeography, and evolutionary history of these species. One example of HGT previously described is of the gene albumin1 from a leguminous host to the common ancestor of Aphyllon, Phelipanche, and Orobanche. Combining Fabaceae fossil evidence and the albumin1 gene tree, these authors were able to infer the timing of the HGT event and subsequent diversification. Taking this a step forward, I used their estimate as a secondary calibration in a more comprehensive divergence time analysis, overcoming the limitation of a poor fossil record. My results support a more recent diversification and evolution of parasitism than previous estimates, which could be due to previous estimates not accounting for the accelerated rates of molecular evolution characteristic in parasitic plants.


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1 - University Of Toronto Mississauga, Department Of Biology, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada

Keywords:
Orobanchaceae
horizontal gene transfer
Phylogenetics
chronogram
divergence time.

Presentation Type: Oral Paper
Number:
Abstract ID:86
Candidate for Awards:George R. Cooley Award


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