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Contrasting patterns of pollen and seed flow influence the spatial genetic structure of sweet vernal grass (Anthoxanthum odoratum) populations

Freeland, Joanna R.; Biss, Pamela and Silvertown, Jonathan (2012). Contrasting patterns of pollen and seed flow influence the spatial genetic structure of sweet vernal grass (Anthoxanthum odoratum) populations. Journal of Heredity, 103(1) pp. 28–35.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1093/jhered/esr111
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Abstract

The spatial genetic structure of plant populations is determined by a combination of gene flow, genetic drift, and natural selection. Gene flow in most plants can result from either seed or pollen dispersal, but detailed investigations of pollen and seed flow among populations that have diverged following local adaptation are lacking. In this study, we compared pollen and seed flow among 10 populations of sweet vernal grass (Anthoxanthum odoratum) on the Park Grass Experiment. Overall, estimates of genetic differentiation that were based on chloroplast DNA (cpDNA) and, which therefore resulted primarily from seed flow, were lower (average FST = 0.058) than previously published estimates that were based on nuclear DNA (average FST = 0.095). Unlike nuclear DNA, cpDNA showed no pattern of isolation by adaptation; cpDNA differentiation was, however, inversely correlated with the number of additions (nutrients and lime) that each plot had received. We suggest that natural selection is restricting pollen flow among plots, whereas nutrient additions are increasing seed flow and genetic diversity by facilitating the successful germination and growth of immigrant seeds. This study highlights the importance of considering all potential gene flow mechanisms when investigating determinants of spatial genetic structure, and cautions against the widespread assumption that pollen flow is more important than seed flow for population connectivity in wind-pollinated species.

Item Type: Journal Article
Copyright Holders: 2011 The American Genetic Association
ISSN: 0022-1503
Keywords: chloroplast DNA; gene flow; genetic diversity; local adaptation; Park Grass Experiment
Academic Unit/Department: Science > Life, Health and Chemical Sciences
Science > Environment, Earth and Ecosystems
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 32368
Depositing User: Jonathan Silvertown
Date Deposited: 06 Feb 2012 09:21
Last Modified: 23 Oct 2012 14:19
URI: http://oro.open.ac.uk/id/eprint/32368
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