The nucleotide homology of MVV-am and 85/34 strain compared with MVV-1514 is is highly variable, which is about 90.1%.

• 结论:我们保存的来源于美国的MVV毒株与原美国株MVV-85/34相比；核苷酸发生了变异；同源性大约为96.；9%25。 而与亲本株MVV-1514相比；核苷酸变异相对较大。