cryptic mutation - (Jul/04/2007 )

Who knows what CRYPTIC MUTATION means?

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I quote B. C. Lamb in the preface of his article in Molec. gen. Genet. 137, 305--314 (1975):

"Cryptic mutations are undetected base changes in genetic DNA (or hereditary RNA). Some kinds of base change are normally undetected; others may or may not be detected, depending on experimental conditions, procedures and genotypes. Cryptic mutations could affect gene conversion results because when heterozygous they cause mismatched base pairs in hybrid DNA in the same way as known mutations, but the experimenter is unaware of them. Cryptic heterozygosity will usually be much more frequent in heterothallic than homothallic organisms. The effects of cryptic mutation heterozygosity on recombination and conversion of known mutations are predicted with reference to co-conversion, map expansion and polarity. Relevant evidence is considered."

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Thanks for your reply. But what does it mean? Undetected by molecular techniqes? Or undetected by the cellular replication/transcription system? And why are they undetected. What makes them so special that they can not be detected?

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It means that the mutation occurs, but is not experimentally detectable, e.g. there is no, or only a very slight, phenotypic effect.

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Typically, it refers to codon "wobble", where a codon has been mutated, often in the third base, but the variant codes for the same amino acid. If it is common enough, it could be considered a single nucleotide polymorphism, or SNP. SNPs have been associated with a variety of things, and are the current darlings of genomic research for disease gene markers.

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