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Abstract Detail


Ferguson, Carolyn [1], Mayfield, Mark [1].

Phlox and the puzzle of polyploidy: an overview of ploidy level data for the genus placed within the context of taxonomy and phylogeny.

The genus Phlox (Polemoniaceae) is an important study system for systematics and evolutionary biology, and holds great promise for ongoing investigation by a diversity of researchers. Polyploidy is particularly noteworthy in Phlox, and while it has sometimes confounded studies within the group, the prevalence of polyploidy in the genus also presents opportunities for intriguing work. Over the course of our research on Phlox, we have accumulated many new chromosome counts (including counts for some taxa from which chromosome counts were previously unknown: P. austromontana, P. diffusa, P. hirsuta, P. pattersonii, P. pilosa subsp. longipilosa and P. speciosa), and we present example counts, along with summary data. Taken together with chromosome counts previously reported in the literature, one or more chromosome counts are now documented for nearly 70% of the 61 species of the genus. Of these species, one or more polyploid counts are known for over one quarter, and multiple cases of both tetraploids and hexaploids are known. Furthermore, intraspecific variation in ploidy level (cytotypic variation) is documented by chromosome counts for several species (and this phenomenon is evidenced by flow cytometry to be fairly common within the genus). Flow cytometry was used to measure DNA content per nucleus (relative 2C genome size) for taxa with reported chromosome counts. At the diploid level (2n=14), estimates of DNA content for Phlox range from ca. 8–14 picograms; and for Phlox polyploids, DNA content increases roughly in proportion to the increase in number of chromosomes (i.e., tetraploids have approximately double the DNA content values of closely related diploids). Ploidy level data for the genus are presented in the framework of current taxonomy, based on available voucher herbarium specimens. These data show that polyploidization has occurred in diverse lineages of the genus, and patterns of genome size are also discussed relative to phylogeny. Overall, available ploidy level data serve as foundational information for this system and also point to the importance of polyploidy in Phlox.

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1 - Kansas State University, Herbarium and Division of Biology, Manhattan, KS, 66506-4901, USA

chromosome number
flow cytometry

Presentation Type: Poster
Session: P, Systematics
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PSY023
Abstract ID:963
Candidate for Awards:None

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