On The Big Challenges of a Small Shrub: Ecological Genetics of Salix herbacea L
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
The response of plants to climate change is among the main questions in ecology and evolution. Faced with changing conditions, populations may respond by adapting, going extinct or migrating. Fine-scale environmental variation offers a unique mosaic to explore these alternatives. In this thesis, I used ecological surveys, field experiments and molecular methods to study the range of possible responses at a very local scale in the alpine dwarf willow Salix herbacea L. Since gene flow may impact the potential for adaptation and migration, I first explored whether phenological divergence driven by snowmelt patterns impacts gene flow. I found that sites with late snowmelt work as sinks of the genetic diversity, as compared to sites with early snowmelt. I also used a combined approach that looked at the selection, heritability and genomic architecture of ecologically-relevant traits, as well as genomic divergence across the snowmelt mosaic. In this way, I was able to understand which genomic regions may relate to phenological, growth and fitness traits, and which regions in the genome harbor genetic variation associated with late- and early- snowmelt sites. I found that most of the genomic divergence driven by snowmelt is novel and is localized in few regions. Also, Salix herbacea has a strong female bias. Sex bias may matter for adaptation to climate change because different sexes of many dioecious species differ in several functions that may fluctuate with changing conditions. I found that the bias is uniform across environments and is already present at seeds and seedlings. A polygenic sex determination system together with transmission distortion may be maintaining the bias. Overall, fast-evolving microhabitat-driven genomic divergence and, at the same time, genetically-based trait variation at a larger scale may play a role for the ability of S. herbacea to persist in diverse and variable conditions.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. , 37 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1288
Fine-scale environmental variation, migration, adaptation, snowmelt timing
Research subject Biology
IdentifiersURN: urn:nbn:se:uu:diva-262239ISBN: 978-91-554-9337-0OAI: oai:DiVA.org:uu-262239DiVA: diva2:852917
2015-10-28, Zootissalen, Evolutionsbiologiskt centrum (EBC), Norbyvägen 18, Uppsala, 13:00 (English)
Pannell, John, PhD
Sophie, KarrenbergLexer, Christian, PhD
ProjectsSNSF Sinergia Salix
List of papers