Patent No. 599237 Disclosed is a double stranded nucleic acid molecule having structure (A) set forth below: (A) 5&rsquo N1-(N)x - Z 3&rsquo (antisense strand) 3&rsquo Z&rsquo-N2-(N&rsquo)y &ndashz&rdquo 5&rsquo (sense strand) wherein each of N2, N and N&rsquo is an unmodified or modified ribonucleotide, or an unconventional moiety wherein each of (N)x and (N&rsquo)y is an oligonucleotide in which each consecutive N or N&rsquo is joined to the adjacent N or N&rsquo by a covalent bond wherein each of x and y is independently an integer between 17 and 39 wherein the sequence of (N&rsquo)y has complementarity to the sequence of (N)x and the sequence of (N)x has complementarity to a consecutive sequence in a target RNA wherein N1 is covalently bound to (N)x and forms a Watson-Crick base pair with N2 wherein N1 is not complementary to the corresponding nucleotide in the target RNA wherein N1 is selected from the group consisting of natural or modified adenosine, and deoxyadenosine when the corresponding nucleotide in the target RNA sequence is adenosine or N1 is selected from the group consisting of natural or modified adenosine, deoxyadenosine, deoxyuridine, deoxythymidine and ribothymidine when the corresponding nucleotide in the target RNA sequence is cytidine or N1 is selected from the group consisting of natural or modified adenosine, deoxyadenosine, uridine, deoxyuridine, ribothymidine and deoxythymidine when the corresponding nucleotide in the target RNA sequence is guanosine or N1 is selected from the group consisting of natural or modified uridine, deoxyuridine, ribothymidine and deoxythymidine when the corresponding nucleotide in the target RNA sequence is uridine wherein z&rdquo may be present or absent, but if present is a capping moiety covalently attached at the 5&rsquo terminus of N2- (N&rsquo)y and wherein each of Z and Z&rsquo is independently present or absent, but if present is independently 1-5 consecutive nucleotides, consecutive non-nucleotide moiet
