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Genetics Research International
Volume 2015, Article ID 835624, 19 pages
http://dx.doi.org/10.1155/2015/835624
Research Article

Genome-Wide Gene Expression in relation to Age in Large Laboratory Cohorts of Drosophila melanogaster

1Biology Department, University of Nebraska at Kearney, Kearney, NE 68849, USA
2Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE 68198, USA
3Department of Genetics, Cell Biology, and Anatomy, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
4School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA

Received 18 November 2014; Revised 2 April 2015; Accepted 2 April 2015

Academic Editor: Patrizio Dimitri

Copyright © 2015 Kimberly A. Carlson et al. 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.

Abstract

Aging is a complex process characterized by a steady decline in an organism’s ability to perform life-sustaining tasks. In the present study, two cages of approximately 12,000 mated Drosophila melanogaster females were used as a source of RNA from individuals sampled frequently as a function of age. A linear model for microarray data method was used for the microarray analysis to adjust for the box effect; it identified 1,581 candidate aging genes. Cluster analyses using a self-organizing map algorithm on the 1,581 significant genes identified gene expression patterns across different ages. Genes involved in immune system function and regulation, chorion assembly and function, and metabolism were all significantly differentially expressed as a function of age. The temporal pattern of data indicated that gene expression related to aging is affected relatively early in life span. In addition, the temporal variance in gene expression in immune function genes was compared to a random set of genes. There was an increase in the variance of gene expression within each cohort, which was not observed in the set of random genes. This observation is compatible with the hypothesis that D. melanogaster immune function genes lose control of gene expression as flies age.