title: Adaptive evolution of pelvic reduction in sticklebacks by recurrent deletion of a Pitx1 enhancer.
abstract: The molecular mechanisms underlying major phenotypic changes that have evolved repeatedly in nature are generally unknown. Pelvic loss in different natural populations of threespine stickleback fish has occurred through regulatory mutations deleting a tissue-specific enhancer of the Pituitary homeobox transcription factor 1 (Pitx1) gene. The high prevalence of deletion mutations at Pitx1 may be influenced by inherent structural features of the locus. Although Pitx1 null mutations are lethal in laboratory animals, Pitx1 regulatory mutations show molecular signatures of positive selection in pelvic-reduced populations. These studies illustrate how major expression and morphological changes can arise from single mutational leaps in natural populations, producing new adaptive alleles via recurrent regulatory alterations in a key developmental control gene.
authors.affiliation: Department of Developmental Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
authors.forename: Yingguang Frank
authors.initials: YF
authors.lastname: Chan
authors.forename: Melissa E
authors.initials: ME
authors.lastname: Marks
authors.forename: Felicity C
authors.initials: FC
authors.lastname: Jones
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Villarreal
authors.forename: Michael D
authors.initials: MD
authors.lastname: Shapiro
authors.forename: Shannon D
authors.initials: SD
authors.lastname: Brady
authors.forename: Audrey M
authors.initials: AM
authors.lastname: Southwick
authors.forename: Devin M
authors.initials: DM
authors.lastname: Absher
authors.forename: Jane
authors.initials: J
authors.lastname: Grimwood
authors.forename: Jeremy
authors.initials: J
authors.lastname: Schmutz
authors.forename: Richard M
authors.initials: RM
authors.lastname: Myers
authors.forename: Dmitri
authors.initials: D
authors.lastname: Petrov
authors.forename: Bjarni
authors.initials: B
authors.lastname: Jónsson
authors.forename: Dolph
authors.initials: D
authors.lastname: Schluter
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bell
authors.forename: David M
authors.initials: DM
authors.lastname: Kingsley
mesh_terms: D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D043283:Chromosome Fragile Sites; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D021901:DNA, Intergenic; D004742:Enhancer Elements, Genetic; D029941:Fish Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D051761:Paired Box Transcription Factors / Q000235:genetics*; D010388:Pelvis / Q000033:anatomy & histology; D012641:Selection, Genetic; D017384:Sequence Deletion; D023701:Smegmamorpha / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D021901:DNA, Intergenic; D029941:Fish Proteins; D051761:Paired Box Transcription Factors; C101485:homeobox protein PITX1