Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:For instance, in a genetically derived all-cone retina mouse model lacking cone Pde6c (Nrl / ;cpfl1), it was demonstrated that the cones instead expressed the rod Pde6 catalytic subunits conferring phototransduction capability to the cones.(32) Similarly, in the rd10 mouse (which lacks the rod Pde6b gene), the cone Pde6a0 subunit was transgenically expressed in the mutant rd10 rods and this rescued the response to light, demonstrating that cone Pde6a0 can functionally substitute for Pde6ab.
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