Table 1. Summary of the sequence requirements of dimeric and tetrameric G-quadruplexes.

Experiment	Result for a dimer-forming sequence	Result for a tetramer-forming sequence	Evidence
Mutagenesis of the central tetrad	NNGG required	GGNN required	Figures 4A and 5A
5′ tetrad swap	Possible	Not possible	Figures 6A and 7A
3′ tetrad swap	Not possible	Not possible	Figures 6A and 7A
Point mutations in loops	A, C or T possible	A, C or T possible	Figures 6B and 7B
Total number of mutations in loops	One to five possible	One to two possible	Figures 6C and 7C
Mixing with a different dimer-forming sequence	Dimers formed	Dimers formed	Figure 8A and B
Mixing with a different tetramer-forming sequence	Dimers formed	Dimers and tetramers formed	Figure 8A and B
Addition of a 5′ overhang	Possible	Not possible (dimer formed instead)	Figure 9A and C
Addition of a 3′ overhang	Possible	Possible	Figure 9A and C