Poly-labelled oligonucleotide derivative

Claim 1

A poly-labelled oligonucleotide derivative represented by the following formula [I]: ##STR5## wherein: either one of R 1 and R 2 is a group represented by the formula [II] shown below and the other is a hydrogen atom or a phosphate group, or both of R 1 and R 2 are groups represented by the formula [II] shown below; n is a natural number from 6 to 200; and B is nucleotide base selected from the group consisting of adenine, thymine, cytosine and guanine; ##STR6## wherein: a is a natural number from 2 to 50 and b is a natural number from 1 to 50, with b+1≧a; R 3 is an alkylene group having 2 to 20 carbon atoms; X represents an oxygen atom or an imino group; (Lys) b represents a lysine moiety when b=1 and a polylysine moiety when b=2 to 50, wherein said polylysine is a polymerization product of lysine through the reaction of its amino group and its carboxylic group with the number of molecules of lysine polymerized therein being equal to b, and wherein (Lys) b is bonded to the moiety --NH-- in formula [II] through reaction of the carboxylic group in the (Lys) b moiety; Y is a label which is selected from the group consisting of biotin, haptens, fluorophores, and chemiluminescent substances, and which is covalently bonded to the (Lys) b moiety through reaction with the amino group or groups in the (Lys) b moiety.