Table 1 Chargaff symmetric observables appear with similar frequency in the human chromosome 1.

From: The common origin of symmetry and structure in genetic sequences

X = XA **** XB P(X) \({{\boldsymbol{z}}}_{[{{\boldsymbol{X}}}_{{\boldsymbol{A}}}{\boldsymbol{,}}{{\boldsymbol{X}}}_{{\boldsymbol{B}}}]}({\boldsymbol{\ell }}{\boldsymbol{=}}{\bf{4)}}\)
CC **** TC GA **** GG 0.00401 0.00404 1.236 1.242
GG **** GA TC **** CC 0.00366 0.00366 1.127 1.128
GG **** TC GA **** CC 0.00302 0.00299 0.929 0.922
CC **** GA TC **** GG 0.00265 0.00264 0.818 0.813
  1. Each line contains an observable X constructed combining oligonucleotides α1α2α8 where α1α2 equal to XA, α3α4α5α6 are arbitrary (any in {A, C, T, G}), and α7α8 equal to XB. Observables related by the extended Chargaff symmetry (3) appear on top of each other (separated by an horizontal line). The frequency of each observable P(X) was computed using Eq. (1) and the normalized version (cross correlation) \({z}_{[{X}_{A},{X}_{B}]}(\ell =\mathrm{4)}\) using Eq. (5).