But many of these are plastic, or nonheritable changes to an individual's physical traits.

但是对于个体的生理特征来说，许多变化都是可塑的，即不能够遗传的变化。

So, the distinction is we're interested in the amount of variation due to genetic differences, not the proportion of an individual's trait that's due to genes.

所以， 区别在于我们对由基因差异引起的变异程度感兴趣，而不是针对个体特质中由基因决定的比例。