Abstract Detail



Reticulate evolution and biogeography in ferns and lycophytes - a colloquium honoring Dr. David Barrington

Jorgensen, Stacy [1].

Polyploid speciation in the Polystichum of the Sierra Talamanca.

Polyploidy is a significant factor in the evolution of plant genomes, and the ferns are no exception. Approximately one-third of fern and lycophyte species are known polyploids. The genus Polystichum is particularly rife with polyploidy, with 44% of the genus estimated to be polyploid. Here, I explore the biogeography and evolutionary history of three polyploid Polystichum species from the neotropics. The Andes are host to a center of diversity for Polystichum, with 26 species. Another center of diversity, known as the Mayan alliance, is found in Mexico and Central America, where 18 species occur. A waypoint between the Andean and Mayan diversity hotspots, the Sierra Talamanca of Costa Rica and Panama harbors three allotetraploid species of Polystichum, two of which are endemic to the range, along with eight diploids and an array of hybrids. In general, the species occurring in the páramos belong to the Andean alliance, while those found in the forests belong to the Mayan alliance. The polyploid taxa incorporate the legacy of the two regions into their genomes: Polystichum gelidum appears to be derived from two distinct Andean progenitors. Polystichum lilianae and P. talamancanum, the two endemic tetraploids, appear to be derived from some combination of Mayan and Andean parentage. Dave has been studying Polystichum in Costa Rica for over forty years, and unravelling the genomic legacy of Mayan and Andean lineages in the tetraploids of the Sierra Talamanca has been a work in progress in the Barrington lab for quite some time. New insight into the evolutionary history and taxonomy of the tetraploids and their candidate progenitors has enabled further advances in this line of inquiry.


1 - Elias Ave, Tucson, AZ, 85719, USA

Keywords:
reticulate evolution
polyplopidy
speciation
biogeography
ferns.

Presentation Type: Colloquium Presentations
Number: 0012
Abstract ID:831
Candidate for Awards:None


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