Table 3.

Base pair characters for sense or antisense direction.

Base pair (primer base–template base)	Primer-template				Primer hairpin or dimer
	Initial stage		Middle stage
	Forward	Reverse	Forward	Reverse
A-T, T-A	a	f	p	u	k
C-G, G-C	b	g	q	v	l
A-A, A-G, G-A, G-G, C-C	c	h	r	w	m
T-T, T-C, C-T	d	i	s	x	n
C-A, A-C, G-T, T-G	e	j	t	y	o

A symbol for generating pseudo-words for RNN learning. The codes are set in the nucleotide duplex on each base pair at the complementary position. Mismatched base pairs such as A-A, T-T and C-A may appear within the partially complementary region. Base-pairs are grouped based on influence for stability of partially complementary strands.