Some of those high-fat diets elicit long-term effects, such as obesity in adulthood in mice and lipotoxic cardiomyopathy of subsequent generations in Drosophila; mechanistically, these effects are manifested partly by altering the DNA methylation status of the FGF21 gene and the systemic H3K27 trimethylation level, respectively (Yuan et al, 2018; Guida et al, 2019). The gene discussed is FGF21; the disease is obesity due to melanocortin 4 receptor deficiency.