Paramutation

Paramutation is a unique interaction between two alleles of a single locus, whereby one allele induces a heritable modification in the other allele without modifying the DNA sequence. This phenomenon was first discovered in maize by Barbara McClintock in 1956.

Overview

Paramutation is a well-documented example of epigenetic phenomena, where heritable changes in gene expression occur without a change in DNA sequence. It involves a transfer of information from one allele to another, leading to a change in expression of the latter. This change is then stably inherited over generations, even in the absence of the inducing allele.

Mechanism

The exact mechanism of paramutation is not fully understood, but it is thought to involve changes in chromatin structure that are brought about by small RNA molecules. These changes are then maintained through DNA replication and cell division, leading to a stable and heritable change in gene expression.

Examples

Paramutation has been observed in a number of organisms, including maize, mice, and Drosophila. In maize, paramutation occurs at the b1 locus, which controls kernel color. In mice, paramutation has been observed at the Kit locus, which affects coat color.

Implications

The study of paramutation has important implications for our understanding of genetic inheritance and gene regulation. It also has potential applications in genetic engineering and crop improvement.

See also

• Epigenetics
• Allele
• Gene expression
• Chromatin
• RNA

References

Paramutation Resources
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