Our extensive microarray analysis indicated that change in gene expression in the cells treated with 18-mer antisense oligonucleotides was significantly smaller than those with a 14-mer antisense oligonucleotide.

Our data showed that the extension of antisense oligonucleotides reduced off-target effects in the light of the reduced number of off-target genes and the reduced extent of gene down-regulation.

Mismatches, insertions, and deletions between the antisense oligonucleotide and the complementary RNA sequences are better tolerated when longer antisense oligonucleotides cleave complementary RNAs.