Table 1.

Representing the set of possible nucleotides after each flow

Flow No.	Flow nucleotide	Candidates	Remaining sequence	Signal
1	A	ACGT	GCCT	0
2	C	CGT	GCCT	0
3	G	GT	GCCT	1
4	T	ACT	CCT	0
5	A	AC	CCT	0
6	C	C	T	2
7	G	AGT	T	0
8	T	AT	—	1

Note: Here, the wash cycle is ACGT and the sequenced string is GCCT. Initially, any nucleotide is possible—the candidates are ACGT. The first flow (A) produces no incorporation signal; therefore, the candidates for the next nucleotide are CGT. After an incorporation event, as in flows 3 and 6, the candidate nucleotides for the next base in the sequence are all the nucleotides except for the one that was just incorporated.