However, our microarray study did, whereas our RNA-seq study did not, identify IGFBP2 and IGFBP3 (genes encoding IGF1 binding proteins) as SDE (≤2-fold) in SNEB cow liver.
In contrast IL-6, which is an acute response cytokine [ 5] and was not identified as a significantly changed gene in our microarray study, did not exhibit significant difference in expression over time by the RT-PCR analysis.
Likewise, lack of expression in microarray studies does not necessarily exclude a gene from being involved in models other than the one in which the studies were undertaken.
The other two microarray studies done with CEU LCLs contained fewer IRF5 probes.
There remains considerable debate in the literature as to why comparative microarray studies do not completely coincide with each other.
Except for complex light harvesting, proteins, microarray studies did not identify significant expression changes in genes of the other proteins, highlighting the importance of proteomic studies.
There remains considerable debate in the literature as to why comparative microarray studies do not completely coincide with each other [ 10].
In addition, many microarray studies do not match the MAQC platform quality, experimentation expertise and relative high signal-to-noise ratios of the samples compared, and would thus generate data of yet poorer reliability.
As with other microarray studies done on older mammalian muscle [ 13- 17], we have also found a disproportionate number of metabolic genes, such as those involved in lipid and carbohydrate metabolism, decrease in transcription levels with age.
In agreement with previous microarray studies done on skeletal muscle of mice, monkeys and humans, we also found that genes associated with metabolic functions, particularly energy pathways, were higher in young control animals (Table 1).
