Table 2. Thermal melting (T _m) data for oligonucleotide duplexes.

Entry	Oligomers	T m  a °C	T m  b
1	18 + 20	62.4 (61.9)	N/A
2	18 + 21	56.1 (54.7)	–6.3 (–7.2)
3	18 + 22	55.1 (54.1)	–7.3 (–7.8)
4	19 + 20	58.5 (58.2)	N/A
5	19 + 21	56.6 (55.3)	–1.9 (–2.9)
6	19 + 22	54.1 (52.8)	–4.4 (–5.4)

^a T _m values for 3 μM oligo samples. Values in parentheses refer to cooling curves.

^b ΔT _m per modification relative to the control DNA 20.