RRC ID 32746
Author Koga A, Wakamatsu Y, Kurosawa J, Hori H.
Title Oculocutaneous albinism in the i6 mutant of the medaka fish is associated with a deletion in the tyrosinase gene.
Journal Pigment Cell Res
Abstract Three mutant alleles (i1, i4, and i5) of the tyrosinase gene in the i locus of the medaka fish Oryzias latipes have hitherto been described, all being associated with transposable element insertion. We have recently identified another allele causing a complete albino phenotype in homozygous carriers and named it i6. Sequence comparison between the tyrosinase gene for the i6 allele (Tyr-i6) and the wild-type gene previously obtained (Tyr-i+) revealed three deletions of 8, 44, and 245 bp. The first two deletions reside in an intron and are differences in the number of tandem tetranucleotide repeats that are polymorphic even among wild-type genes, and, thus, not likely to be responsible for the i6 albino phenotype. The largest deletion spans over the last 180 bp of the second intron and the first 65 bp of the third exon. Because of this deletion, the Tyr-i6 gene lacks the branch point sequence and the acceptor site for the second intron, both being considered to be necessary for normal RNA splicing. Therefore, the 245-bp deletion is likely to be responsible for the albino phenotype. With a mutant gene of this type, unlike ones bearing transposable element insertions, the possibility of reversion mutations to the wild-type would be negligible. Therefore, fish having the i6/i6 genotype should serve as superior recipients for the tyrosinase gene in rescue experiments.
Volume 12(4)
Pages 252-8
Published 1999-8-1
DOI 10.1111/j.1600-0749.1999.tb00758.x
PMID 10454293
MeSH Albinism, Oculocutaneous / genetics* Albinism, Oculocutaneous / veterinary* Alleles Animals Base Sequence Female Fish Diseases / genetics* Genetic Variation Male Molecular Sequence Data Monophenol Monooxygenase / genetics* Mutation Oryzias / genetics* Polymorphism, Restriction Fragment Length Repetitive Sequences, Nucleic Acid Sequence Deletion
Times Cited 11
Medaka MT72