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United States Department of Agriculture

Agricultural Research Service

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Research Project: Phylogeography and Conservation Genetics of the Caribbean Zamia Clade: An Integrated Systematic Approach

Location: Subtropical Horticulture Research

2013 Annual Report


1a.Objectives (from AD-416):
The Zamia pumila L. complex (Cycadales: Zamiaceae) is a distinctive, monophyletic, diploid (2n =16) assemblage of populations restricted to the West Indies and southeastern U. S. that is currently considered to encompass either a single polymorphic, or nine distinct species. They are important landscape ornamentals in USDA Zones 9-11. The proposed research seeks to simultaneously complete extensive microsatellite DNA and phylogeographic sequence analyses using single copy nuclear genes across the complex and apply these data to various systematic, evolutionary, conservation and biogeographic questions. Results of this project will be interpreted within the context of the complex environmental history of the region. We anticipate that an understanding of the genetic structure of the populations of this complex will help to delineate future conservation strategies, and serve as a model for population level studies of other rare Caribbean plant taxa.


1b.Approach (from AD-416):
Twenty-five to 50 individuals from 1-10 populations from each island in the West Indies known to harbor extant Zamia populations [Bahamas (Andros, Eleuthera, Grand Bahama, Great Abaco, Long Island, New Providence), Cuba (15-20 populations), Grand Cayman, Jamaica, Hispaniola, Puerto Rico] will be sampled. Populations from Puerto Rico, Dominican Republic, Jamaica and four of six Bahamian islands have already been sampled. Collections on Cuba will be supported by non-Federal funds. Twenty-five populations from Florida sufficient to cover the geographic breadth of the distribution of Zamia throughout the southeast U. S. will also be sampled. It is estimated that the total number of populations that will be sampled will range from 80 to 120, with 3600-4500 individuals genotyped with 25 SSR primers, and 1200 individuals will be sequenced across 10 nuclear genes. Bayesian approaches, Maximum Likelihood and the coalescent model will form the framework by which the SSR data will be analyzed. Phylogeographic analysis will be conducted with new software applications that handle gene tree heterogeneity, and a phylogenetic approach for evaluating conservation priority in the group will be evaluated.


3.Progress Report:

This research is directly related to inhouse objective 1. Characterize and evaluate priority NPGS woody landscape and herbaceous subtropical/tropical plant germplasm for key traits, such as their taxonomic identity, genetic variability, and ornamental merit, thereby enhancing the utility of these genetic resources for research and breeding.

Genotyping is complete for all Zamia populations from Florida, Dominican Republic, Jamaica, Puerto Rico, The Bahamas, and The Cayman Islands across a minimum of 25 microsatellite DNA loci (from a library of 32). Sequencing of a subset of samples from all of these populations across 10 single copy nuclear genes is complete for Puerto Rico, Jamaica, Dominican Republic, and substantially completed for Florida and the Bahamas. Collaborators are in Cuba, making the first of what will be 3-4 sampling trips for Zamia populations. Analyses are of the microsatellite DNA is complete for Puerto Rico, Jamaica, Dominican Republic, and the Bahamas and will be a source of publications next year.


Last Modified: 9/10/2014
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