Comparative genetic structure of two mangrove species in Caribbean and Pacific estuaries of Panama

BMC Evolutionary Biology

Research Article

Eldredge Bermingham¹  William Owen McMillan¹  Frank Andrew Jones²  Ivania Cerón-Souza³ 

[1] Smithsonian Tropical Research Institute, 0843-03092, Apartado, Panama;Smithsonian Tropical Research Institute, 0843-03092, Apartado, Panama;Department of Botany and Plant Pathology, Oregon State University, 2070 Cordley Hall, 97331, Corvallis, OR, USA;Smithsonian Tropical Research Institute, 0843-03092, Apartado, Panama;University of Puerto Rico, Rio Piedras Campus, PO BOX 23360, 00931-3360, San Juan, Puerto Rico;

关键词: Rhizophora mangle;    Avicennia germinans;    Pollen dispersal;    Seed dispersal;    Spatial genetic structure;   

DOI  :  10.1186/1471-2148-12-205

 received in 2012-06-15, accepted in 2012-10-11,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundMangroves are ecologically important and highly threatened forest communities. Observational and genetic evidence has confirmed the long distance dispersal capacity of water-dispersed mangrove seeds, but less is known about the relative importance of pollen vs. seed gene flow in connecting populations. We analyzed 980 Avicennia germinans for 11 microsatellite loci and 940 Rhizophora mangle for six microsatellite loci and subsampled two non-coding cpDNA regions in order to understand population structure, and gene flow within and among four major estuaries on the Caribbean and Pacific coasts of Panama.ResultsBoth species showed similar rates of outcrossing (t= 0.7 in A. germinans and 0.8 in R. mangle) and strong patterns of spatial genetic structure within estuaries, although A. germinans had greater genetic structure in nuclear and cpDNA markers (7 demes > 4 demes and Sp= 0.02 > 0.002), and much greater cpDNA diversity (Hd= 0.8 > 0.2) than R. mangle. The Central American Isthmus serves as an exceptionally strong barrier to gene flow, with high levels nuclear (FST= 0.3-0.5) and plastid (FST= 0.5-0.8) genetic differentiation observed within each species between coasts and no shared cpDNA haplotypes between species on each coast. Finally, evidence of low ratios of pollen to seed dispersal (r = −0.6 in A. germinans and 7.7 in R. mangle), coupled with the strong observed structure in nuclear and plastid DNA among most estuaries, suggests low levels of gene flow in these mangrove species.ConclusionsWe conclude that gene dispersal in mangroves is usually limited within estuaries and that coastal geomorphology and rare long distance dispersal events could also influence levels of structure.

【 授权许可】

CC BY   
© Cerón-Souza et al.; licensee BioMed Central Ltd. 2012