DoD TATRC Retina Dataset Affymetrix MouseGene 2.0 ST Array (____ 2015) RMA analysis and scaling by Arthur Centeno. This data set consists of 75 BXD strains, C57BL/6J, DBA/2J, both reciprocal F1s, and BALB/cByJ. A total of 80 strains were quantified. The data are now open and available for analysis.

This is RMA expression data that has been normalized using what we call a 2z+8 scale, but without special correction for batch effects. The data for each strain was computed as the mean of four samples per strain. Expression values on a log2 scale range from 6.25 to 18.08 (11.83 units), a nominal range of approximately 3600-fold. After taking the log2 of the original non-logged expression estimates, we convert data within an array to a z score. We then multiply the z score by 2. Finally, we add 8 units to ensure that no values are negative. The result is a scale with a mean expression of the probes on the array of 8 units and a standard deviation of 2 units. A two-fold difference in expression is equivalent roughly to 1 unit on this scale.

The lowest level of expression is 6.254 for ILMN_2747167 (Arhgap11a) from HEI Retina Illumina V6.2 (April 2010) RankInv **. Lowest single data about 5.842. The highest level of expression is 18.077 for ILMN_2516699 (Ubb). Highest single value is about 18.934.