CLU and retinal degeneration: In addition to aberrant photoreceptor marker gene expression, our data also suggested that the expression of macroglial genes (Müller glia and astrocytes) was higher in the affected dog (Figure 8), most notably clusterin (CLU) and glial fibrillary acidic protein (GFAP) expression (Table S4), both of which are known to be upregulated under retinal stress and retinal degeneration [110,111,112,113].