Allelic exclusion

Allelic exclusion is a process by which only one allele of a gene is expressed while the other allele is silenced. For autosomal genes, diploid organisms inherit one copy from each parent.

At least two distinct selection events can lead to allelic exclusion. On one hand, one allele of the gene can be transcriptionally silent, which would result in the expression of only the second allele. On the other hand, both alleles can be transcribed, in which case posttranscriptional and posttranslational mechanisms will lead to the elimination of the protein product of one allele.