Fitness effects associated with the major flowering time gene FRIGIDA in Arabidopsis thaliana in the field.
To date, the effect of natural selection on candidate genes underlying complex traits has rarely been studied experimentally, especially under ecologically realistic conditions. Here we report that the effect of selection on the flowering time gene FRIGIDA (FRI) reverses depending on the season of germination and allelic variation at the interacting gene FLOWERING LOCUS C (FLC). In field studies of 136 European accessions of Arabidopsis thaliana, accessions with putatively functional FRI alleles had higher winter survival in one FLC background in a fall-germinating cohort, but accessions with deletion null FRI alleles had greater seed production in the other FLC background in a spring-germinating cohort. Consistent with FRI's role in flowering, selection analyses suggest that the difference in winter survival can be attributed to time to bolting. However, in the spring cohort, the fitness difference was associated with rosette size. Our analyses also reveal that controlling for population structure with estimates of inferred ancestry and a geographical restriction was essential for detecting fitness associations. Overall, our results suggest that the combined effects of seasonally varying selection and epistasis could explain the maintenance of variation at FRI and, more generally, may be important in the evolution of genes underlying complex traits.
Korves
Tonia M
TM
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA. tonia_korves@brown.edu
Schmid
Karl J
KJ
Caicedo
Ana L
AL
Mays
Charlotte
C
Stinchcombe
John R
JR
Purugganan
Michael D
MD
Schmitt
Johanna
J
D000704:Analysis of Variance; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D004843:Epistasis, Genetic; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D026161:MADS Domain Proteins / Q000235:genetics; D012237:Rhode Island; D012621:Seasons; D012641:Selection, Genetic; D016019:Survival Analysis
D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; C414613:FRI protein, Arabidopsis; D026161:MADS Domain Proteins