Scientific question for atheists...?

Knowing what we know about genetics, would you consider the following thesis to be PLAUSIBLE. If animals today (such as dogs) belong to families and are all related but have "evolved" through micro-evolution so that the genes/traits that they keep are the ones that help them survive. Would it be plausible that Noah's arc could have existed and could have repoplulated the world if the animals on board all had pure heterogeneous genotypes (consisting on a dominant and recessive gene Bb).