A method for screening the effect of a segment A (chemical species A) on a substance (for example, a cell) containing DNA or RNA by using artificial chemical species. Namely, a method of detecting or identifying the function of a chemical species A on a substance containing DNA or RNA by using one or more chemical species represented by the following general formula (I) which are capable of recognizing a DNA base sequence; a kit therefor; and a plate to be used therein: B-L-A (I) wherein B represents a chemical structure containing an non-natural base capable of recognizing a DNA base sequence; A represents a chemical structure having an interaction with DNA; and L represents a linker whereby the chemical structures A and B can be linked together.