Are your FlexiTube siRNAs preferentially designed to any particular region of the target gene?

No, the design of Flexitube siRNAs in GeneGlobe is not biased towards either the 3' or the 5' end of the target gene.

A number of siRNAs are located in the 3' untranslated region for optimized specificity of the siRNA sequences to their target gene. Since there are homologous sequences in the coding regions of other genes for many targets, it is usually easier to find highly unique siRNA sequences in the untranslated regions. Such design ensures highly specific silencing effects for the gene of interest.