Abstract Detail


Ramadoss, Niveditha [1], McElwee-Adame, Alexandra [2], Parker, V. T. [3], Gonzalez-Elizondo, Socorro [4], Litt, Amy [5], Flores-Renteria, Lluvia [6].

A genome-wide approach for resolving phylogenetic relationships of subfamily Arbutoideae (Ericaceae).

Arbutoideae is a monophyletic subfamily in the Ericaceae family that comprises six genera - Arbutus, Arctostaphylos, Arctous, Comarostaphylis, Ornithostaphylos, and Xylococcus. Most of these taxa are adapted to summer-dry or strongly seasonal climates. In these regions, several species have been suggested to have historically shifted from forest to shrublands with accompanying changes in morphological features such as bird-dispersed fleshy fruits to mammal scattered dry fruits. However, their phylogenetic relationships have long been unclear. According to a previous study, Arbutus is a paraphyletic genus with the North American taxa forming a clade separate from the European taxa. But this paraphyletic phylogeny was based on markers that are prone to duplication, low bootstrap values and incomplete species sampling in Arbutus. Thus, the goal of our project is to reconstruct the phylogenetic relationships of subfamily Arbutoideae with genome-wide reliable SNP markers and increased sampling of Arbutus species. This phylogeny will be used to explore the morphological diversity among the genera and test the monophyly of genus Arbutus. At least 3 samples representing 31 species across all genera were collected. The SNP data were generated by a next generation sequencing technique called DartSeq which allows the detection of a high number of informative SNPs across the genome. The relationships were tested using model based (Maximum Likelihood (ML) and Bayesian analysis) and non-model based (Discriminant Analysis of Principal Components (DAPC), Neighbor-joining tree) approaches. Preliminary results based on DAPC show that the North American Arbutus is genetically distinct from European Arbutus. The phylogenetic analyses were performed without the outgroups as they had a lot of missing data. Instead the root placement was inferred in the ML tree by using non-reversible models in IQ-TREE2. Based on this method, the highest statistical confidence to place the root was on the node leading to the Comarostaphylis species. In addition, the preliminary Bayesian tree inferred similar relationships as ML tree between the genera. A well resolved phylogeny will be used as the basis for morphological character state mapping with Mesquite. We will map characters such as fruit morphology, fruit maturation season, endocarp traits, germination strategy etc for each genus. This will help us understand if those character changes are shared or evolved independently. Overall our research will be useful in resolving the taxonomic uncertainty and understanding the evolutionary processes in Arbutoideae.

1 - 6621 MONTEZUMA ROAD APT 207, 6621 MONTEZUMA ROAD APT 207, SAN DIEGO, CA, 92115, United States
2 - 5070 1/2 Niagara Ave, San Diego, CA, 92107, United States
3 - 5353 La Jolla Blvd, Unit 37, San Diego, CA, 92037, United States
4 - Instituto Politécnico Nacional, CIIDIR, Mexico
5 - University Of California Riverside, Botany Dept, 900 University Ave, Riverside, CA, 92521, United States
6 - San Diego State University, 4319 Yale Ave, San Diego State University, La Mesa, CA, 91942, United States

Arbutus paraphyly.

Presentation Type: Oral Paper
Number: PHYLO II014
Abstract ID:347
Candidate for Awards:None

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