People might expect “affected by genes” to be an objective fact not related to the current variation of genes we actually have. For example, let’s say there’s a

People might expect “affected by genes” to be an objective fact not related to the current variation of genes we actually have. For example, let’s say there’s a gene that reduces lifespan by 1 year that half of people have. If this gene spread so that in the future everyone had the gene, lifespan would suddenly be “less affected by genes” than before. (Because variation in this gene no longer exists, genetic variation will have less effect on lifespan.) But of course, lifespan is still being affected by this gene.