Table 1

Notation

Parameter

Description

A

Adenine content

T

Thymine content

G

Guanine content

C

Cytosine content

GC

Guanine-plus-cytosine content, GC = G + C

S

Guanine-plus-cytosine content, S = G + C

R

Purine (adenine-plus-guanine) content, R = A + G

A_i

Adenine content at codon position i, i = 1, 2, 3

T_i

Thymine content at codon position i, i = 1, 2, 3

G_i

Guanine content at codon position i, i = 1, 2, 3

C_i

Cytosine content at codon position i, i = 1, 2, 3

S_i

Guanine-plus-cytosine at codon position i, S_i = G_i + C_i, i = 1, 2, 3

R_i

Purine content at codon position i, R_i = A_i + G_i, i = 1, 2, 3

Zhang and Yu Biology Direct 2010 5:63   doi:10.1186/1745-6150-5-63