The present invention provides an
insect odorant receptor co-
receptor that exhibits excellent detection sensitivity of odorants when bound with an
odorant receptor to form an
odorant receptor complex.This odorant
receptor co-
receptor is provided with the following first
amino acid sequence and second
amino acid sequence which follows the
amino acid residue furthest on the carboxyl-terminal side of the first amino acid sequence: (1) a first amino acid sequence which is a partial amino acid sequence of an odorant receptor co-receptor of a first
insect or a variant of the receptor, and which isan amino acid sequence that is continuous from the amino-terminal of the first
insect odorant receptor co-receptor or the variant thereof to any
amino acid residue positioned in the range of 20 aminoacid residues before and after the
amino acid residue furthest on the carboxyl-terminal side in the fourth
transmembrane domain; and (2) a second amino acid sequence which is a partial amino acid sequence of an odorant receptor co-receptor of a second insect of a different variety than the first insect or a variant of the receptor, and which, in an alignment analysis of the amino acid sequence ofthe first insect odorant receptor co-receptor or the variant thereof and the amino acid sequence of the second insect odorant receptor co-receptor or the variant thereof, is an amino acid sequence that is continuous from one carboxyl-terminal-side
amino acid residue, said residue being in a position in the second insect odorant receptor co-receptor or the variant thereof that corresponds to the amino acid residue furthest on the carboxyl-terminal side of the first amino acid sequence, to the carboxyl-terminal of the second insect odorant receptor co-receptor or the variant thereof.