The mouse pink-eyed unstable (pun) mutation, affecting coat color, exhibits one of the highest reported reversion frequencies of any mammalian mutation and is associated with a duplication of genomic DNA at the p locus. In this study, genomic clones containing the boundaries of the pun duplication were isolated and characterized. The structure of these sequences and their wild-type and revertant counterparts were analyzed by restriction mapping, PCR product analysis, DNA sequence analysis, and pulsed-field gel electrophoresis. DNA from pun was distinguished from wild-type and revertant DNA by a head-to-tail tandem duplication of ≈70 kilobases. No differences were detected between revertant and wild-type DNAs. Thus, the reversion in phenotype of pun mice is coupled with the loss of one copy of an ≈70-kilobase duplicated segment. Testable models are presented to account for pun reversion.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Jan 1 1993|
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