A century and a half after we first probed heritability, we risk forgetting one of Mendel's own basic findings, in rushing to broaden clinical genomics to lifelong care for all. Embracing that key insight now -- as we long have in tracking the chemistry of health -- can help gird our health infrastructure for the long haul.

Learning objectives

• Conventionally, we clinically classify and report genomic variants.
• That habit -- rooted in early clinical genomics (reading few genes, in few people, mostly sick) -- presumes that disease cases trace mainly to strongly acting single variants...so sweeps widespread real impenetrance, for major diseases, under a vast rug.
• Classifying and reporting genotypes would more neatly and realistically track non-additive genomic interactions mined from emerging data, girding healthcare for broad longterm genomic utility.
•  The history of toxicology (and of early genetics too!) starkly highlights this lesson, and suggests simple but urgent steps that stakeholders (genomicists, informaticians, caregivers, and patients) should take now.