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Title: Genetic structure of the threatened Phaedranassa schizantha (Amaryllidaceae)

Author
item OLEAS, NORA - Universidad Technologica Indoamerica, Biocamb, Machala Y Sabarilla
item Meerow, Alan
item ORTEGA, JAVIER - Florida International University

Submitted to: Botanical Journal of the Linnean Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2016
Publication Date: 8/16/2016
Citation: Oleas, N., Meerow, A.W., Ortega, J. 2016. Genetic structure of the threatened Phaedranassa schizantha (Amaryllidaceae). Botanical Journal of the Linnean Society. 182:169-179.

Interpretive Summary: Population genetic analysis can provide important information for the conservation of endangered species. Phaedranassa schizantha Baker (Amaryllidaceae) is an endangered species found only in Ecuador. Taxonomically P. schizantha was described as two varieties: P. schizantha var. schizantha and P. schizantha var. ignea Meerow. We assessed the population genetic structure of 11 populations across the species’ range with 13 nuclear repeat DNA markers. Our data show that in general allele richness was lower at the southern portion of the geographic range, and it was especially low in populations closest to cities. We found significant population differentiation and evidence of genetic bottleneck. Genetic variation did not show isolation by distance. Instead, results suggest genetic barriers around two main cities. Data supports a relatively recent divergence pattern (<10,000 years ago) from south to north. Two genetic groups can be identified, neither of which is represented by either of the two taxonomic varieties previously recognized. Conservation efforts need to be taken to facilitate the genetic exchange between the genetic groups, especially between locations that seem to be genetically isolated.

Technical Abstract: Population genetic analysis can provide important information for the conservation of endangered species. Phaedranassa schizantha Baker (Amaryllidaceae) is an endangered species endemic to Ecuador. Taxonomically P. schizantha was described as two varieties: P. schizantha var. schizantha and P. schizantha var. ignea Meerow. We assessed the population genetic structure and demographic patterns of 11 populations across the species’ range with 13 microsatellite loci. Our data show that in general allele richness was lower at the southern portion of the geographic range, and it was especially low in populations closest to cities. We found significant population differentiation (Dest = 0.34) and evidence of genetic bottleneck. Genetic variation did not show isolation by distance. Instead, results suggest genetic barriers around two main cities. Coalescent analysis indicates a relatively recent divergence pattern (<10,000 years ago) from south to north. Bayesian analysis identified two genetic groups, neither of which is represented by either of the two taxonomic varieties previously recognized. Conservation efforts need to be taken to facilitate the genetic exchange between the genetic groups, especially between locations that seem to be genetically isolated.