title: The genetic architecture of parallel armor plate reduction in threespine sticklebacks.
abstract: How many genetic changes control the evolution of new traits in natural populations? Are the same genetic changes seen in cases of parallel evolution? Despite long-standing interest in these questions, they have been difficult to address, particularly in vertebrates. We have analyzed the genetic basis of natural variation in three different aspects of the skeletal armor of threespine sticklebacks (Gasterosteus aculeatus): the pattern, number, and size of the bony lateral plates. A few chromosomal regions can account for variation in all three aspects of the lateral plates, with one major locus contributing to most of the variation in lateral plate pattern and number. Genetic mapping and allelic complementation experiments show that the same major locus is responsible for the parallel evolution of armor plate reduction in two widely separated populations. These results suggest that a small number of genetic changes can produce major skeletal alterations in natural populations and that the same major locus is used repeatedly when similar traits evolve in different locations.
authors.affiliation: Department of Developmental Biology and Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Pamela F
authors.initials: PF
authors.lastname: Colosimo
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Peichel
authors.forename: Kirsten
authors.initials: K
authors.lastname: Nereng
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Blackman
authors.forename: Michael D
authors.initials: MD
authors.lastname: Shapiro
authors.forename: Dolph
authors.initials: D
authors.lastname: Schluter
authors.forename: David M
authors.initials: DM
authors.lastname: Kingsley
mesh_terms: D000483:Alleles; D000825:Animal Structures; D000818:Animals; D005075:Biological Evolution; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D019143:Evolution, Molecular; D005260:Female; D005816:Genetic Complementation Test; D014644:Genetic Variation; D005838:Genotype; D008297:Male; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D040641:Quantitative Trait Loci; D012641:Selection, Genetic; D023701:Smegmamorpha / Q000033:anatomy & histology* / Q000196:embryology*