Abstract Detail

Systematics

Abbo, Tito [1], Morrison, Glen [2], Huang, Yi [3], Parker, V. T. [4], Jolles, Diana [5], Stoughton, Thomas [6], Sanders, Andrew [1], Litt, Amy [7].

Manzanita phylogenomics: Untangling species relationships in a hyperdiverse shrub complex.

Within the mecca of species-richness of the California floristic province, Arctostaphylos Adans. is the most diverse genus of shrubs and is of high importance in chaparral ecosystems. It contains c. 105 taxa, most are found exclusively in California and are of conservation concern. The vast diversity of Arctostaphylos is paralleled by its challenging taxonomy and obscure phylogenetic relationships. Taxonomic identification is complicated by relative uniformity of floral characters, high variability among descriptive characters such as pubescence, and limited access to material from rare and remote taxa. Equally, the genus features tetraploid taxa of putative hybrid origin, and widespread introgression is assumed. Early molecular attempts to evaluate current taxonomic classifications and elucidate species relationships focused on the nuclear ITS region. These studies identified an early divergence into two sister clades but failed to resolve terminal taxa. Our current study aims to tackle these challenges with phylogenomic approaches. We have thus far sampled 55 species (with 5 or more individuals per species in most cases), and we are conducting preliminary phylogenomic analyses using ddRAD-seq data and are finding support for a majority of recognized diploid species but inconclusive results for tetraploid species. Tetraploid taxa such as A. glandulosa appear to have affinities with multiple diploid taxa possibly due to independent hybrid origins of morphologically similar taxa or secondary introgression with other tetraploid taxa. To arrive at a consistent and robust phylogenetic hypothesis, our long term goal is to evaluate the data using a variety of methods including concatenation, and coalescence-based species tree estimation, and maximum likelihood and Bayesian statistics. This research will help systematists better understand speciation in complex woody genera and may shed light on the processes that lead to diversification and endemism within the California floristic province.

1 - University of California Riverside, 900 University Ave, Riverside, California, 92521, United States
2 - University Of California Riverside, Botany And Plant Sciences, 900 University Ave, Riverside, CA, 92521, United States
3 - University of California Riverside, Botany and Plant sciences, 900 University Ave, Riverside, California, 92521, United States
4 - 503 Goodman Rd, Pacifica, CA, 94044, United States
5 - 19 Warren Street, Plymouth, NH, 03264, United States
6 - Plymouth State University, 17 High Street, Plymouth, New Hampshire, 03264
7 - University Of California, Riverside, Botany And Plant Sciences, 900 University Avenue, Riverside, CA, 92521, United States

Keywords:
none specified

Presentation Type: Oral Paper
Session: COOLI, ASPT Cooley Award Talks I
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 10:45 AM(EDT)
Number: COOLI004
Abstract ID:584
Candidate for Awards:George R. Cooley Award