Evolution Quote by Robert M. Sapolsky

““Study a gene in only one environment and, by definition, you’ve eliminated the ability to see if it works differently in other environments (in other words, if other environments regulate the gene differently). And thus you’ve artificially inflated the importance of the genetic contribution. The more environments in which you study a genetic trait, the more novel environmental effects will be revealed, decreasing the heritability score. Scientists study things in controlled settings to minimize variation in extraneous factors and thus get cleaner, more interpretable results—for example, making sure that the plants all have their height measured around the same time of year. This inflates heritability scores, because you’ve prevented yourself from ever discovering that some extraneous environmental factor isn’t actually extraneous.fn22 Thus a heritability score tells how much variation in a trait is explained by genes in the environment(s) in which it’s been studied.””

— Robert M. Sapolsky