Ratios and Housekeeper NormalizationJustin R Brown* and Valentin Dinu
Department of Biomedical Informatics, Arizona State University, USA
- *Corresponding Author:
- Justin R Brown
Department of Biomedical Informatics
Arizona State University, 13212 East Shea Boulevard
Scottsdale, AZ 85259, USA
Tel: +1 480-884-0220
E-mail: [email protected]
Received date: September 24, 2015; Accepted date: October 12, 2015; Published date: October 19, 2015
Citation: Brown JR, Dinu V (2015) Ratios and Housekeeper Normalization. J Biom Biostat 6:252. doi:10.4172/2155-6180.1000252
Copyright: ©2015 Brown JR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
A common practice in gene expression studies is to use ‘housekeepers’, i.e., genes expected to be expressed at relatively constant levels across experimental conditions, to normalize data. The process is to divide an expression value by some composite of one or more stable housekeepers to remove the effect of processing and nuance variables. Despite its reverence and widespread use, we argue that this approach is fundamentally flawed on multiple levels. The outcome of housekeeper normalization is a set of ratio variables which are not amenable to many standard statistical tests. There are no universal housekeeper genes and even within specific cohorts proposed housekeeper genes often fail to replicate. Furthermore, there is also no single agreed upon algorithm for performing housekeeper normalization or agreement regarding what constitutes a good housekeeper. We urge researchers to consider the use of alternative methodologies in their research.