Imagine that these white mice differ from their pigmented litter-mates by just a tiny change at one gene in the entire genome, and they're otherwise completely normal.
想像一下, 这些白色的老鼠 与它们有色小同伴不同的原因， 仅是由于在整个基因组中的 一个小改变， 除此之外, 它们几乎一模一样。