Abstract Detail



Phylogenomics

Givnish, Thomas [1], Lemmon, Alan [2], Lemmon, Emily [3], Specht, Chelsea [4], Eifler, Evan [1], Karimi, Nisa [1].

Phylogenomics, floral evolution, and formation of an ornamented ring species-complex in the Bay Area Clade of Calochortus (Liliaceae).

The Bay area clade consists of 10 species with three floral syndromes (cat’s ear, star tulip, fairy lantern), found mainly in California with a center of diversity near San Francisco. Previous analyses based on three plastid loci and nrDNA ITS suggested extensive hybridization. Here we use sequences of ca. 400 single-copy nuclear loci and whole plastomes to infer phylogeny, test for reticulate evolution, and reconstruct floral evolution and historical biogeography. The nuclear phylogeny implies an initial split between albus-amoenus (with white or pink fairy-lantern flowers) and the remaining eight species. Within the latter group, the three yellow fairy-lanterns (amabilis, pulchellus, raichei) form a clade sister to the yellow cat’s-ear monophyllus. This yellow clade is sister to the white/violet cat’s-ear tolmiei. Finally, these are sister to the clade formed by cat’s-ear tiburonensis and the star tulips umbellatus and uniflorus. Conflict among nuclear loci, and between the nuclear and plastome trees, indicate at least five reticulations within the Bay Area clade, most likely involving hybridization. The nuclear tree implies that the ancestral flowers within the Bay Area clade were cat’s ears, with one gain of the star-tulip syndrome and two gains of the fairy-lantern syndrome. Serpentine tolerance arose twice and was lost twice. Biogeographic analyses suggest that the Bay Area clade is an ornamented ring species-complex that surrounds the Central Valley, with two species ranging outside this area into the Cascades. The albus-amoenus complex south of the Golden Gate diverged from other species northwards, with albus on mélange in the south Coast Ranges, Transverse Ranges, and Peninsular Ranges, and disjunctly in the northern Sierra Nevada, and amoenus on granite in the central and southern Sierra. The tiburonensis-umbellatus-uniflorus clade arose in the Bay Area, with uniflorus invading moist mafic meadows to the north, into central Oregon. C. tolmiei, sister to the yellow clade, ranges from the Bay Area to Seattle. Finally, the yellow clade ranges northward from the Golden Gate, with amabilis in the North Coast Ranges and across the north end of the Central Valley, and monophyllus in the northern Sierra. Two microendemics are embedded in amabilisraichei in Sonoma County, and pulchellus, restricted to the Mt. Diablo area. Hybridization occurs frequently between albus and monophyllus, where the two pincers of the ring-species complex overlap in the northern Sierra. Ancient hybridization appears to underlie the formation of pulchellus, where the yellow clade crossed the Sacramento River and overlaps with Coast Ranges albus.


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1 - University Of Wisconsin-Madison, Department Of Botany, 430 Lincoln Drive, Madison, WI, 53706.0, United States
2 - Florida State University, Department of Scientific Computing, 400 Dirac Science Library, Tallahassee, FL, 32306, USA
3 - Florida State University, Biological Science, 123 Biomedical Research Facility, Tallahassee, FL, 32306, United States
4 - Cornell University, School of Integrative Plant Science and L.H. Bailey Hortorium, 502 Mann Library, Ithaca, NY, 14850, USA

Keywords:
historical biogeography
phylogenomics
California Floristic Province
convergence.

Presentation Type: Oral Paper
Session: PHYL3, Phylogenomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:30 AM
Number: PHYL3003
Abstract ID:661
Candidate for Awards:None


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