Hi
CarbonRobotI think
this article answers the question quite effectively:
The key step in the formation of the duplex retina (meaning one consisting of both rods and cones) of vertebrates was the evolution of more sensitive rods to accompany cones, so that the entire range of light intensities could be encoded by the photoreceptors. Molecular and biochemical studies tell us that rods and cones have many of the same transduction proteins but use different isoforms probably arising by gene duplication; in some cases they use the same isoform but at a different level of expression. No one change accounts for the difference in absolute sensitivity between rods and cones. Instead, each of the differences we have described seems to have produced a small increase in the rate of activation or prolongation of response decay, conferring an incremental advantage to the organism.
Accumulated changes in a large number of proteins eventually produced a sensitivity great enough in the rod to allow it to operate in dim light, with cones remaining for enhanced temporal resolution when photon flux is no longer limiting. These changes also have implications for the dynamic properties of rods and cones, namely their ability to adapt to increasing light intensity. The properties of the two receptor types form the basis of our duplex visual system, whose fundamental nature was first proposed by Schultze 150 years ago.
Molecular and biochemical studies tell us that rods and cones have many of the same transduction proteins but use different isoforms probably arising by gene duplicationThis statement gives us a reason to believe that it is possible for cons to be genetically manipulated to behave like rod cells, but a duplex retina is definitely required to see in the depth we can as human beings. The article mentions that
cells resembling cones are very old, first appearing among cnidarians, which implies that cons likely evolved first, leading later to the evolution of rod cells; in fact,
the emergence of rods was a key step in the evolution of the vertebrate eye. Also,
rods and cones have a different anatomy, with only rods containing membranous discs enclosed by the plasma membrane. This further leads me to believe that what you're asking is more complicated than it sounds...
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