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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: Population genetics of Zamia in Puerto Rico, a preliminary study with ten SSR loci

Authors
item Meerow, Alan
item Francisco-Ortega, Javier - FIU DEPT OF BIO SCI
item Ayala-Silva, Tomas
item Stevenson, Dennis - FAIRCHILD TROP BOT GARDEN
item Nakamura, Kyoko

Submitted to: Memoirs of the New York Botanical Garden
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 20, 2009
Publication Date: October 20, 2012
Citation: Meerow, A.W., Francisco-Ortega, J., Ayala Silva, T., Stevenson, D.W., Nakamura, K. 2012. Population genetics of Zamia in Puerto Rico, a preliminary study with ten SSR loci . Memoirs of the New York Botanical Garden. Memoirs of the New York Botanical Garden 106 : 204 – 223.

Interpretive Summary: Three distinctive cycads are found on Puerto Rico, which have been treated as three species: Z. amblyphyllidia, found on the north coast, and Z. portoricensis and Z. pumila, both found in the south. We investigated the population genetics of these species with ten DNA markers across seven populations, three each of the former two, and one of Z. pumila. Puerto Rican zamias exhibit a combination of the patterns of genetic differentiation that have been reported for cycads based on other types of markers. High genetic variation within populations is the rule for all three. Zamia amblyphyllidia exhibits a more than fivefold greater degree of population differentiation than Z. portoricensis, among whose populations gene flow is much higher. Zamia ambliphyllidia has a greater number of unique alleles; Z. pumila has none. Overall, a strong pattern of isolation by distance is evident among Puerto Rican Zamia populations. Significant inbreeding is evident in Z. pumila and two populations of Z. amblyphyllidia, which may be a cause for concern from a conservation perspective.

Technical Abstract: Three distinctive morphotypes of Zamia occur on Puerto Rico, which have been treated as three species: Z. amblyphyllidia, found on the north coast, and Z. portoricensis and Z. pumila, both found in the south. We investigated the population genetics of these species with ten microsatellite DNA loci across seven populations, three each of the former two, and one of Z. pumila. Puerto Rican zamias exhibit a combination of the patterns of genetic differentiation that have been reported for cycads based on allozymes or dominant DNA markers. High infra-populational genetic variation is the rule for all three, perhaps a factor of the high degree of polymorphism in the SSR loci. Zamia amblyphyllidia exhibits a more than fivefold greater degree of population differentiation than Z. portoricensis, among whose populations gene flow is much higher. Zamia ambliphyllidia has a greater number of private alleles; Z. pumila has none. None of the populations appear to have undergone recent bottlenecks, and tests of drift vs. gene flow strongly favor gene flow overall among the populations. Overall, a strong pattern of isolation by distance is evident among Puerto Rican Zamia populations. Zamia amblyphyllidia, Z. pumila and one population of Z. portoricensis are slightly inbred, while two populations of the latter are out-crossing. Significant heterozygote deficiency is evident in Z. pumila and two populations of Z. amblyphyllidia, which may be a cause for concern from a conservation perspective.

Last Modified: 8/30/2014
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