Dataset Information

Limited Pollen Dispersal Contributes to Population Genetic Structure but Not Local Adaptation in Quercus oleoides Forests of Costa Rica.

ABSTRACT:

Background

Quercus oleoides Cham. and Schlect., tropical live oak, is a species of conservation importance in its southern range limit of northwestern Costa Rica. It occurs in high-density stands across a fragmented landscape spanning a contrasting elevation and precipitation gradient. We examined genetic diversity and spatial genetic structure in this geographically isolated and genetically distinct population. We characterized population genetic diversity at 11 nuclear microsatellite loci in 260 individuals from 13 sites. We monitored flowering time at 10 sites, and characterized the local environment in order to compare observed spatial genetic structure to hypotheses of isolation-by-distance and isolation-by-environment. Finally, we quantified pollen dispersal distances and tested for local adaptation through a reciprocal transplant experiment in order to experimentally address these hypotheses.

Results

High genetic diversity is maintained in the population and the genetic variation is significantly structured among sampled sites. We identified 5 distinct genetic clusters and average pollen dispersal predominately occurred over short distances. Differences among sites in flowering phenology and environmental factors, however, were not strictly associated with genetic differentiation. Growth and survival of upland and lowland progeny in their native and foreign environments was expected to exhibit evidence of local adaptation due to the more extreme dry season in the lowlands. Seedlings planted in the lowland garden experienced much higher mortality than seedlings in the upland garden, but we did not identify evidence for local adaptation.

Conclusion

Overall, this study indicates that the Costa Rican Q. oleoides population has a rich population genetic history. Despite environmental heterogeneity and habitat fragmentation, isolation-by-distance and isolation-by-environment alone do not explain spatial genetic structure. These results add to studies of genetic structure by examining a common, tropical tree over multiple habitats and provide information for managers of a successional forest in a protected area.

SUBMITTER: Deacon NJ

PROVIDER: S-EPMC4583504 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Limited Pollen Dispersal Contributes to Population Genetic Structure but Not Local Adaptation in Quercus oleoides Forests of Costa Rica.

Deacon Nicholas John NJ Cavender-Bares Jeannine J

PloS one 20150925 9

<h4>Background</h4>Quercus oleoides Cham. and Schlect., tropical live oak, is a species of conservation importance in its southern range limit of northwestern Costa Rica. It occurs in high-density stands across a fragmented landscape spanning a contrasting elevation and precipitation gradient. We examined genetic diversity and spatial genetic structure in this geographically isolated and genetically distinct population. We characterized population genetic diversity at 11 nuclear microsatellite l ...[more]

PMID: 26407244

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Project description:Rationale: MicroRNAs have emerged as crucial post-transcriptional and network regulators in inflammatory diseases, including asthma. We hypothesized that peripheral blood miRNA would be associated with airflow obstruction in children with asthma, and that some of these effects would also be observable in adults with COPD. Methods: We analyzed small RNA-Seq data from 365 peripheral blood samples from the Genetics of Asthma in Costa Rica Study (GACRS). GACRS comprised children from the Central Valley of Costa Rica age 6-14 years with physician-diagnosed asthma and ≥2 respiratory symptoms or asthma attacks in the prior year. FEV1/FVC percent-predicted was dichotomized at 100%, splitting the cohort into those with and without evidence of airflow obstruction and used as our primary outcome. Differentially expressed (DE) miRs were identified using the DESeq2 package in R with a 10% FDR and adjustment for age, gender, and inhaled corticosteroid (ICS) use. We attempted to replicate the top airflow obstruction-associated microRNAs from the GACRS study in the COPDGene study, in which blood microRNA data were available in 439 current and former smoking adults with and without airflow obstruction (defined as raw FEV1/FVC < 0.7). Results: After QC, we had 361 samples and 649 miRs for DE analysis. Of the 361 samples, 220 and 141 were from subjects without and with airflow obstruction, respectively. We found 1 upregulated (let-7e-5p p=0.0004) and 2 downregulated (miR-342-3p p=0.0002; miR-671-5p p=0.0001) miRs in subjects with airflow obstruction compared to those without airflow obstruction. These three miRNAs were then tested for association with airflow obstruction in the COPDGene study, in which let-7e-5p was upregulated (p = 0.064) and miR-342-3p (p =0.085) was downregulated in participants with FEV1/FVC < 0.7 (n=196) compared to those with FEV1/FVC > 0.7 (n=243). Differentially expressed miR’s target genes were enriched for PI3K-Akt, Hippo, WNT, MAPK, and focal adhesion signaling pathways. We also separately considered the targets of only the two miRNAs that were also associated with FEV1/FVC in the adult current and former smokers, where PI3K-Akt, MAPK and Hippo signaling pathways were among the top five most enriched pathways. Conclusion: Three DE miRs were linked to airflow obstruction in children with asthma. Two miRs were associated with FEV1/FVC in current and former smoking adults. These miRs were involved in asthma and COPD-related pathways: PI3K-Akt, Hippo, MAPK, and focal adhesion signaling pathways. Together these findings provide important evidence that these two disorders may share genetic regulatory systems that contribute to airflow obstruction.

Dataset Information

Limited Pollen Dispersal Contributes to Population Genetic Structure but Not Local Adaptation in Quercus oleoides Forests of Costa Rica.

Background

Results

Conclusion

Publications

Limited Pollen Dispersal Contributes to Population Genetic Structure but Not Local Adaptation in Quercus oleoides Forests of Costa Rica.

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