Table of Contents Author Guidelines
Genetics Research International
Volume 2018, Article ID 7089109, 12 pages
Review Article

Phenotypic Nonspecificity as the Result of Limited Specificity of Transcription Factor Function

Department of Biology, The University of Western Ontario, London, ON, Canada N6A 1B7

Correspondence should be addressed to Anthony Percival-Smith; ac.owu@avicrepa

Received 12 June 2018; Accepted 9 October 2018; Published 28 October 2018

Academic Editor: Martin Kupiec

Copyright © 2018 Anthony Percival-Smith. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Drosophila transcription factor (TF) function is phenotypically nonspecific. Phenotypic nonspecificity is defined as one phenotype being induced or rescued by multiple TFs. To explain this unexpected result, a hypothetical world of limited specificity is explored where all TFs have unique random distributions along the genome due to low information content of DNA sequence recognition and somewhat promiscuous cooperative interactions with other TFs. Transcription is an emergent property of these two conditions. From this model, explicit predictions are made. First, many more cases of TF nonspecificity are expected when examined. Second, the genetic analysis of regulatory sequences should uncover cis-element bypass and, third, genetic analysis of TF function should generally uncover differential pleiotropy. In addition, limited specificity provides evolutionary opportunity and explains the inefficiency of expression analysis in identifying genes required for biological processes.