Studying genetics of adaptive variation in model organisms: flowering time variation in Arabidopsis lyrata

Abstract

Arabidopsis thaliana has emerged as a model organism for plant developmental genetics, but it is also now being widely used for population genetic studies. Outcrossing relatives of A. thaliana are likely to provide suitable additional or alternative species for studies of evolutionary and population genetics. We have examined patterns of adaptive flowering time variation in the outcrossing, perennial A. lyrata. In addition, we examine the distribution of variation at marker genes in populations form North America and Europe. The probability of flowering in this species differs between southern and northern populations. Northern populations are much less likely to flower in short than in long days. A significant daylength by region interaction shows that the northern and southern populations respond differently to the daylength. The timing of flowering also differs between populations, and is made shorter by long days, and in some populations, by vernalization. North American and European populations show consistent genetic differentiation over microsatellite and isozyme loci and alcohol dehydrogenase sequences. Thus, the patterns of variation are quite different from those in A. thaliana, where flowering time differences show little relationship to latitude of origin and the genealogical trees of accessions vary depending on the genomic region studied. The genetic architecture of adaptation can be compared in these species with different life histories.

The evolutionary history of the Arabidopsis lyrata complex: a hybrid in the amphi-Beringian area closes a large distribution gap and builds up a genetic barrier

“…The A. lyrata complex has already proven to be a suitable study system for the analysis of character traits such as flowering time [9,10] or pathogen defense [11]. Additionally, molecular mechanisms for the function of sporophytic self-incompatibility have been investigated [12-20], and comparative approaches to analyse sporophytic self-incompatibility in diploids versus polyploids are underway (Jørgensen, unpublished data).…”

Divergent Selection on Flowering Time Contributes to Local Adaptation in Mimulus Guttatus Populations

“…In plants, the timing of flowering results from interactions between the complex network of genes that controls development (reviewed in Simpson and Dean 2002;Koornneef et al 2004) and specific environmental cues, such as day length (Lacey 1988;Olsson and Å gren 2002;Weinig et al 2002;Griffith and Watson 2005;Riihimaki et al 2005), light level (Stanton et al 2000), temperature (Eckhart et al 2004), time of snowmelt (Stanton et al 1997), nutrient level (Stanton et al 2000), and water availability (Vasek and Sauer 1971;Aronson et al 1992;Fox 1990;Bennington and McGraw 1995;Eckhart et al 2004;Franke et al 2006;Petru et al 2006). Because the optimal timing of flowering may vary tremendously across different habitats, it is reasonable to suspect that populations and closely related species should be genetically divergent in their flowering response to environmental cues.…”

“…Because the optimal timing of flowering may vary tremendously across different habitats, it is reasonable to suspect that populations and closely related species should be genetically divergent in their flowering response to environmental cues. Indeed, many studies have demonstrated genetic divergence in flowering time in nature (Clausen et al 1940;Schemske 1984;Stanton et al 1997;Kittelson and Maron 2001;Eckhart et al 2004;Ceplitis et al 2005;Lempe et al 2005;Riihimaki et al 2005;Franke et al 2006), but unfortunately the extent to which such differentiation contributes to local adaptation often is not clear.…”

Taming the wild: resolving the gene pools of non-model Arabidopsislineages

“…Population-based analysis with a few selected populations provided the first evidence for population genetic structure at varying geographic scales [34-36]. At a more local scale and focusing on different aspects of adaptation there are numerous contributions covering A. lyrata [37-39], and comprehensive reviews have recently been presented to summarize many more aspects [1,40]. There is very limited information regarding A. arenosa , one of the most diverse evolutionary lineages in Arabidopsis [22], with only one phylogeographic-systematic study at a broad geographic scale [19].…”