Genetic markers test assign testresult with 1 if either geneticmarkera is 1 or geneticmarkerb is 1. if geneticmarkera and geneticmarkerb are both 1, then assign testresult with 0. if geneticmarkera and geneticmarkerb are both 0, then assign testresult with 0. ex: if geneticmarkera is 1 and geneticmarkerb is 0, then testresult is assigned with 1. if geneticmarkera is 1 and geneticmarkerb is 1, then testresult is assigned with 0.