title: Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Ambystoma mexicanum.
abstract: The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning-candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyra) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyrahas a 142 bp deletion and similar engineered alleles recapitulated the albino phenotype. Finally, we show that historical introgression of tyrasignificantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl.
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: M Ryan
authors.initials: MR
authors.lastname: Woodcock
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Vaughn-Wolfe
authors.affiliation: Lafayette High School, Lexington, KY, 40503, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Elias
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: D Kevin
authors.initials: DK
authors.lastname: Kump
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: Katharina Denise
authors.initials: KD
authors.lastname: Kendall
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Timoshevskaya
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Timoshevskiy
authors.affiliation: Transposagen Biopharmaceuticals, 535 W 2nd Suite l0, Lexington, KY, 40508, USA.
authors.forename: Dustin W
authors.initials: DW
authors.lastname: Perry
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA.
authors.forename: Jeramiah J
authors.initials: JJ
authors.lastname: Smith
authors.affiliation: Department of Biology, University of Washington, Seattle, WA, 98195, USA.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Spiewak
authors.affiliation: Department of Biology, University of Washington, Seattle, WA, 98195, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Parichy
authors.affiliation: Department of Biology, University of Kentucky, Lexington, KY, 40506, USA. srvoss@uky.edu.
authors.forename: S Randal
authors.initials: SR
authors.lastname: Voss
mesh_terms: D000558:Ambystoma mexicanum / Q000235:genetics*; D000818:Animals; D005075:Biological Evolution; D000073537:Biological Variation, Population; D004247:DNA / Q000235:genetics; D005838:Genotype; D010860:Pigments, Biological / Q000235:genetics*
chemical_list: D010860:Pigments, Biological; D004247:DNA