A method for selecting a candidate oligonucleotide for activating expression of a target gene, the method comprising: selecting a PRC2-associated region within a first nucleotide sequence, wherein the first nucleotide sequence maps to a position in a first chromosome between 50 kilobases upstream of a 5'-end of the target gene and 50 kilobases downstream of a 3'-end of the target gene, wherein the PRC2-associated region is a region of an RNA that is protected from a nuclease in an RNA-immunoprecipitation assay that employs an antibody that targets a component of PRC2; determining a second nucleotide sequence that is complementary with at least 8 consecutive nucleotides of the PRC2-associated region; and selecting as the candidate oligonucleotide, a single stranded oligonucleotide comprising the second nucleotide sequence, wherein the oligonucleotide has at least one of following features: a) a sequence: 5'-X-Y-Z, wherein X is any nucleotide, Y is a nucleotide sequence of 6 nucleotides in length that is not a seed sequence of a human microRNA, and Z is a nucleotide sequence of 1 to 23 nucleotides in length, wherein X is anchored at the 5' end of the oligonucleotide; b) a sequence that does not comprise three or more consecutive guanosine nucleotides; c) a sequence that is complementary to a PRC2-associated region that encodes an RNA that forms a secondary structure comprising at least two single stranded loops; or d) a sequence that has greater than 60% G-C content; wherein the single stranded oligonucleotide is 8 to 30 nucleotides in length. selecting a PRC2-associated region within a first nucleotide sequence, wherein the first nucleotide sequence maps to a position in a first chromosome between 50 kilobases upstream of a 5'-end of the target gene and 50 kilobases downstream of a 3'-end of the target gene, wherein the PRC2-associated region is a region of an RNA that is protected from a nuclease in an RNA-immunoprecipitation assay that employs an antibody that targets a component of PRC2; determining a second nucleotide sequence that is complementary with at least 8 consecutive nucleotides of the PRC2-associated region; and selecting as the candidate oligonucleotide, a single stranded oligonucleotide comprising the second nucleotide sequence, wherein the oligonucleotide has at least one of following features: a) a sequence: 5'-X-Y-Z, wherein X is any nucleotide, Y is a nucleotide sequence of 6 nucleotides in length that is not a seed sequence of a human microRNA, and Z is a nucleotide sequence of 1 to 23 nucleotides in length, wherein X is anchored at the 5' end of the oligonucleotide; b) a sequence that does not comprise three or more consecutive guanosine nucleotides; c) a sequence that is complementary to a PRC2-associated region that encodes an RNA that forms a secondary structure comprising at least two single stranded loops; or d) a sequence that has greater than 60% G-C content; a) a sequence: 5'-X-Y-Z, wherein X is any nucleotide, Y is a nucleotide sequence of 6 nucleotides in length that is not a seed sequence of a human microRNA, and Z is a nucleotide sequence of 1 to 23 nucleotides in length, wherein X is anchored at the 5' end of the oligonucleotide; b) a sequence that does not comprise three or more consecutive guanosine nucleotides; c) a sequence that is complementary to a PRC2-associated region that encodes an RNA that forms a secondary structure comprising at least two single stranded loops; or d) a sequence that has greater than 60% G-C content; wherein the single stranded oligonucleotide is 8 to 30 nucleotides in length.