Neither of my parents share my blood type. If one parent is O and the other AB, the child will only be A or B, this is the case for me. I had a twin that did not make it early in the pregnancy too. I am A and actually strength tested highest for nomad, but had i been B, it would be a tough one to distinguish.
Being A and having an O- and A- maternal lineage (mom and grandma), this was more evidence suggesting explorer.
I am not two toned and although a tad asymetrical side to side, overall could pass for normal in many circles!