Genomic signatures of the plateless phenotype in the threespine stickleback.
Understanding the genetic basis of traits involved in adaptive divergence and speciation is one of the most fundamental objectives in evolutionary biology. Toward that end, we look for signatures of extreme plate loss in the genome of freshwater threespine sticklebacks (Gasterosteus aculeatus). Plateless stickleback have been found in only a few lakes and streams across the world; they represent the far extreme of a phenotypic continuum (plate number) that has been studied for years, although plateless individuals have not yet been the subject of much investigation. We use a dense single nucleotide polymorphism dataset made using RADseq to study fish from three freshwater populations containing plateless and low plated individuals, as well as fish from full plated marine populations. Analyses were performed using FastStructure, sliding windows F ST, Bayescan and latent factor mixed models to search for genomic differences between the low plated and plateless phenotypes both within and among the three lakes. At least 18 genomic regions which may contribute to within-morph plate number variation were detected in our low plated stickleback populations. We see no evidence of a selective sweep between low and plateless fish; rather reduction of plate number within the low plated morph seems to be polygenic.
Department of Biosciences Centre for Ecological and Evolutionary Synthesis University of Oslo PO Box 1066 Blindern Norway.
Anna B
AB
Mazzarella
Department of Biosciences Centre for Ecological and Evolutionary Synthesis University of Oslo PO Box 1066 Blindern Norway.
Sanne
S
Boessenkool
Department of Biosciences Centre for Ecological and Evolutionary Synthesis University of Oslo PO Box 1066 Blindern Norway; Faculty of Applied Ecology and Agricultural Sciences Hedmark University College Campus Evenstad No-2480 Koppang Norway.
Kjartan
K
Østbye
Department of Biosciences Centre for Ecological and Evolutionary Synthesis University of Oslo PO Box 1066 Blindern Norway.
Leif Asbjørn
LA
Vøllestad
Department of Biosciences Centre for Ecological and Evolutionary Synthesis University of Oslo PO Box 1066 Blindern Norway; Department of Botany and Biodiversity Research University of Vienna Rennweg 14A-1030 Vienna Austria.
Emiliano
E
Trucchi
Bayescan; Gasterosteus aculeatus; RADseq; latent factor mixed models; lateral plates