10. Appendix

Here is the appendix information.

10.1. Correspondence Between Bases and Chars

Char	Base	Char	Base	Char	Base	Char	Base
A	A	B	C, G, T	C	C	D	A, G, T
E	null	F	null	G	G	H	A, C, T
I	A, G, C, T	J	null	K	G, T	L	null
M	A, C	N	A, G, C, T	O	null	P	null
Q	null	R	A, G	S	G, C	T	T
U	T	V	A, G, C	W	A, T	X	null
Y	C, T	Z	A

Remarks:

1. null means the program will just skip the character when read strings;

2. Degenerate symbols will be handled using rule of frequency, for example: ‘M’ will be regarded as 50% A + 50% C and vectorized as \([0.5, 0, 0.5, 0]\);

3. ‘I’ means hypoxanthine and may be paired with any type of bases;
   ‘Z’ means diaminopurine and can only be paired with ‘A’. (Zhou Y, et al. Science, 2021, 372(6541): 512-516.)

10.2. ZcurvePy Source Code

ZcurvePy is a free open source software follows the MIT license, so you can view the source code or change in my code repository: https://github.com/zetong-zhang/zcurvepy/