Volcano plots of miR expression in P347S and wild-type retinas. Plots represent comparative microRNA (miR) expression profiles of (a) c57 versus 129 retinas, (b) c57 versus P347S (mutant pro347ser RHO transgene) retinas, and (c) 129 versus P347S retinas using Ambion miR microarrays. X-axis indicate difference of expression level on a log2 scale, while y-axis represents corresponding P values (Student's t-test) on a negative log scale; more lateral and higher points mean more extensive and statistically significant differences, respectively. Red lines indicate differences of ± 1 and significance level of P = 0.05. Labels are given for miRs with changes of higher than ± 1 (P < 0.05). MiR-1, miR-96, miR-133, and miR-183 are highlighted in red; h and m in labels refer to human and mouse miRs.