Adaptive evolution of pelvic reduction in sticklebacks by recurrent deletion of a Pitx1 enhancer.
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.
Chan
Yingguang Frank
YF
Department of Developmental Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
Marks
Melissa E
ME
Jones
Felicity C
FC
Villarreal
Guadalupe
G
Shapiro
Michael D
MD
Brady
Shannon D
SD
Southwick
Audrey M
AM
Absher
Devin M
DM
Grimwood
Jane
J
Schmutz
Jeremy
J
Myers
Richard M
RM
Petrov
Dmitri
D
Jónsson
Bjarni
B
Schluter
Dolph
D
Bell
Michael A
MA
Kingsley
David M
DM
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
D021901:DNA, Intergenic; D029941:Fish Proteins; D051761:Paired Box Transcription Factors; C101485:homeobox protein PITX1