Initial mutational steps toward loss of opsin gene function in cavefish.
The river-dwelling fishes of Astyanax fasciatus and their derivatives from Pachon and Micos caves in Mexico were collected. By comparing red (r007) and green (g103) opsin gene sequences from the three populations, we found a high frequency of C-->T changes in r007 and g103 of the eyed Micos fishes presumably due to spontaneous cytosine methylation or enzymatic deamination of the CG dinucleotide, and a deletion of 12 consecutive nucleotides in g101 of the blind Pachon fishes. Thus, high rates of nucleotide substitution and C-->T transitions, usually found for pseudogenes, may occur even before they become nonfunctional.
Yokoyama
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Department of Biology, Syracuse University, NY 13244-1220, USA.
Meany
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Wilkens
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Yokoyama
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R
D000818:Animals; D001766:Blindness / Q000235:genetics; D005091:Exons; D005399:Fishes / Q000235:genetics*; D005796:Genes / Q000502:physiology; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D007438:Introns; D016296:Mutagenesis; D009154:Mutation; D017299:Rod Opsins / Q000235:genetics*; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid
D017299:Rod Opsins