The ambiguous boundary between genes and pseudogenes: the dead rise up, or do they?

Deyou Zheng, Mark B. Gerstein

Research output: Contribution to journalArticle

78 Scopus citations


Pseudogenes have long been considered to be 'dead', nonfunctional by-products of genome evolution. However, several lines of evidence now show that some pseudogenes are transcriptionally 'alive', and a few might even have biochemical roles. Therefore, the boundary between genes (often considered to be 'living') and pseudogenes (often considered to be 'dead') might be ambiguous and difficult to define. Here, we examine the evidence for and against pseudogene functionality, and we argue that the time is ripe for revising the definition of a pseudogene. Furthermore, we suggest a classification system to accommodate pseudogenes with various levels of functionality.

Original languageEnglish (US)
Pages (from-to)219-224
Number of pages6
JournalTrends in Genetics
Issue number5
StatePublished - May 1 2007
Externally publishedYes


ASJC Scopus subject areas

  • Genetics

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