The table shows the distribution of B6 and 129 alleles in mice from the two genetic backgrounds. An initial analysis was performed on 3 samples and a second analysis on 8 more samples. Only the markers that were not uniformly B6 alleles are shown. Some of the markers were refined based on the initial analysis, so not all markers were used for all 11 mice. (*) Eleven samples were analyzed but one sample was ambiguous.