2 2  Example: 2 chromosomes with 2 loci each
5 7
6    North
n_ind0_a  Gaaaa
n_ind0_b  aGaaa
n_ind1_a  aaGaa
n_ind1_b  aaaGa
n_ind2_a  aaaaG
n_ind2_b  Taaaa
n_ind0_a  Caaaaaa
n_ind0_b  aCaaaaa
n_ind1_a  aaCaaaa
n_ind1_b  aaaCaaa
n_ind2_a  aaaaCaa
n_ind2_b  aaaaaCa
4    South
s_ind0_a  Taaaa
s_ind0_b  aTaaa
s_ind1_a  aaTaa
s_ind1_b  aaaTa
s_ind0_a  Gaaaaaa
s_ind0_b  aGaaaaa
s_ind1_a  aaGaaaa
s_ind1_b  aaaGaaa