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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION, CHARACTERIZATION, AND GENETIC IMPROVEMENT OF SUBTROPICAL AND TROPICAL ORNAMENTAL GERMPLASM

Location: Subtropical Horticulture Research

Title: A molecular phylogeny of Zamia L.: a multi-gene approach using single-copy nuclear genes

Authors
item Calonje, Michael -
item Meerow, Alan
item Griffith, Patrick -
item Salas-Leiva, Dayana -
item Francisco-Ortega, Javier -
item Vovides, Andrew -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2012
Publication Date: N/A

Interpretive Summary: The genus Zamia, with approximately 70 species, is the most morphologically and ecologically diverse genus in the Cycadales, and an important and high value tropical ornamental. We present a tree of life for the genus using five single-copy nuclear genes in an analysis including over 90% of the currently accepted species in the genus. The genus Zamia appears to have originated in the Caribbean basin and dispersed through Central America into South America. Major groups are strongly congruent with geographic distribution, agreeing with the limited gene flow and dispersal ability of the Cycadales. In addition, parallel evolution of morphological characters appears to be common in the genus.

Technical Abstract: The genus Zamia, with approximately 70 species, is the most morphologically and ecologically diverse genus in the Cycadales. We present the preliminary results of a multi-gene phylogenetic analysis of the genus Zamia including over 90% of the currently accepted species in the genus. A concatenated matrix containing intron regions of five single-copy nuclear genes was analyzed using maximum parsimony and likelihood phylogenetic inference methods, the latter using a mixed-model analysis with optimal substitution rates applied. A gene tree/species tree reconciliation analysis is also presented. The genes used in the analysis include: Cy-AGAM (Cycas Agamous), a C MADS-box gene thought to control reproductive organ identity; PEX4, a gene encoding for a peroxisomal ubiquitin conjugating enzyme; PMP22, a gene encoding for a peroxisomal membrane 22 kDA family protein; ATG2, a gene encoding for a metallopeptidase M24 family protein, and WRKY4, a gene encoding for transcriptional regulators. PCR protocols for these genes were developed at the labs at the USDA and FTBG. Major clades and novel phylogenetic relationships are discussed within the context of biogeography and comparative macromorphology. The genus Zamia appears to have originated in the Caribbean basin and dispersed through Central America into South America. Major clades are strongly congruent with geographic distribution, agreeing with the limited gene flow and dispersal ability of the Cycadales. In addition,convergent evolution of macromorphological characters appears to be common in the genus.

Last Modified: 8/27/2014
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