Beck, James , Allison, James , Pryer, Kathleen , Windham, Michael .
Identifying multiple origins of polyploid taxa: a multilocus study of the hybrid cloak fern (
Almost thirty years ago, isozyme analyses of a small group of ferns provided the first solid evidence that a single polyploid species could have multiple, independent origins. Subsequent molecular studies have shown that this is the rule rather than the exception among polyploid taxa scattered across the tree of life. In order to understand the distribution and ecology of particular polyploid species, and the evolutionary significance of polyploidy in general, it is important to delineate these independently-derived lineages as accurately as possible. Unfortunately, gene flow among polyploid lineages and backcrossing to their diploid parents often confound this process. Such post-origin gene flow is less of an issue in asexual polyploids where independent lineages generally maintain their genetic distinctiveness. In this study, we use multilocus data to identify independently-derived lineages within the apomictic allopolyploid fern Astrolepis integerrima; (Pteridaceae). This morphologically heterogeneous species is most common in the southwestern US and Mexico, with outlying populations in the southeastern US and Caribbean. Taken together, phylogenetic analysis of plastid DNA sequence and multidimensional clustering of AFLP genotype data identify ten genetic groups within the 33 analyzed samples. These groups suggest a minimum of ten origins of A. integerrima in the northern portion of its range, and our results highlight the extreme cryptic genetic diversity and systematic complexity that can underlie a single polyploid taxon.
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1 - Wichita State University, Biology, 1845 Fairmount, Box 26, Wichita, KS, 67260-0026, USA
3 - Duke University, Science Drive, Durham, NC, 27708-0338, USA
4 - DUKE UNIVERSITY, Department Of Biology, BOX 90338, DURHAM, NC, 27708, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Delaware B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 10:15 AM