Figure 16. QTL signatures for cells and tissue types. Five cohorts of transcripts (n=20) were generated using signature genes listed in Table 2: Aebp1 (sclera), Aldh3a1 (cornea), Cd68 (anterior segment and macrophages), Chrna6 (retinal ganglion cells), and Chat (starburst amacrine cells). Each row in this figure is color-coded by the strength and polarity of genetic control. Chromosome regions that exert strong control are either blue (B alleles contribute to higher expression) or red (D alleles contribute to higher expression). Each tissue type has one or more chromosomal regions with relatively consistent QTL peaks. In contrast, the strong modulation by a QTL near Tyrp1 on Chr 4 is a notable feature across several cell and tissue types. How to identify QTL networks modulating tissue specific gene expression: Step1. Follow the steps in the legend of Figure 8 to generate a set of 10 of more transcripts that covary with signature transcripts listed in Table 2. Step 2. Place the transcript data sets into your BXD Trait Collection (maximum is approximately 100). Step 3. Select traits in your BXD Collection and click on the 'QTL Heat Map' button.