Amico, Guillermo C. , Nickrent, Daniel .
Phylogeography of the mistletoe Tristerix corymbosus (Loranthaceae) inferred from chloroplast DNA sequences.
THE mistletoe Tristerix corymbosus is distributed from 30º S in Chile to 42º S in Chile and Argentina. Throughout this range this species is present in two habitats, the temperate forest and the more recent Chilean matorral which formed ca. 5 mybp. We examined chloroplast sequence variation among populations covering the entire range of the species. Given the recency of the matorral habitat, we postulate that mistletoe populations found here have derived from forest populations. To test this hypothesis we conducted molecular analyses of two non-coding chloroplast regions: the atpB–rbcL spacer and the trnT-L-F region. A network was constructed with statistical parsimony and phylogenetic relationships between haplotypes were assessed using parsimony, likelihood and Bayesian analyses. The trnT-L-F region is less informative than the atpB-rbcL spacer; hence only one individual per populations was sequenced from it. Sequences for the atpB-rbcL spacer were obtained from 108 individual in 26 populations. The network structure for both chloroplast regions was congruent. For the atpB–rbcL spacer, eight haplotypes were identified that did not correspond simply to matorral and forest types, but were placed in three clades (here designated A, B, C). Only three populations had more than one haplotype. Several phenomena at different geological times may have influenced the present spatial pattern and genetic differentiation of T. corymbosus populations. The uplift of the Andes had a great impact, first dividing a widespread ancestral haplotype (clade A). After glaciations, one of the clade B haplotypes may have dispersed south from refugia in central Chile. Although the original hypothesis was confirmed, the northernmost matorral populations of clade C were most similar to the forest populations (not the geographically closer southern ones), thus indicating the presence of a northern refugium. These localities have already been inferred to be refugia for other plants and animals.
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Loranthaceae page on Parasitic Plant Connection
1 - Universidad Nacional del Comahue, CRUB, Laboratorio de Ecotono, Quintral 1250, Bariloche, RN, 8400, Argentina
2 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, August 1st, 2006
Time: 9:30 AM