Abstract Detail

Systematics Section / ASPT

Kim, Sang-Tae [1], Donoghue, Michael J. [1].

LEAFY intron phylogeny and hybrid speciation in Polygonum section Persicaria (Polygonaceae) of eastern North America.

Polygonum section Persicaria (Mill.) Meisn. consists of about 70 speceis of weedy herbs found in moist or disturbed areas. Previous sequence analyses of nuclear (ribosomal ITS) and chloroplast (matK) DNA from eastern North American species suggested the hybrid origin of P. punctatum and the possibility of cytoplasmic introgression involving two American and one introduced species. In order to understand those interspecific relationship more clearly, we carried out sequence analyses of the nuclear low-copy gene LEAFY second intron (PL2INT) from 12 eastern North American species. The length of amplified intron region ranged from 731 to 1053 bp, with the number of copies being generally consistent with ploidy level. In the gene tree, one of the two PL2INT copies from tetraplod P. punctatum is allied with a copy from diploid P. hydropiper, and the other one links with one of three copies from hexaploid P. puritanorum. This result strongly supports the hypothesized hybrid origin of P. punctatum based previously on the incongruence of nrITS and cpmatK trees.

1 - Yale University, Department of Ecology and Evolutionary Biology, P.O. Box 208105, New Haven, Connecticut, 06520-8105, USA

Keywords:
Polygonum
Persicaria
phylogeny
polyploidy
LEAFY
Intron DNA
hybridization.

Presentation Type: Poster
Session: 32-93
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:571