The distribution of GCC differences between human and mouse. (A) The distribution of GCC differences between H1 and M2; (B) the distribution of GCC differences between H2 and M2; (C) the distribution of GCC differences between M1 and M2; (D) the distribution of GCC differences between H1 and H2; (E) the distribution of GCC differences between H1 and M1; (F) the distribution of GCC differences between H2 and M1.