How birds thrive on sugar diets—and what it reveals about human metabolism
Scientists have identified the genetic switches that allow hummingbirds, parrots, and other species to safely consume high-sugar diets without metabolic disease. The discovery of a key regulatory gene called MLXIPL, which evolved differently across multiple bird lineages, could unlock new treatments for obesity, diabetes, and metabolic disorders affecting billions of people worldwide.
Originaltitel: Convergent and lineage-specific genomic changes shape adaptations in sugar-consuming birds
High-sugar diets cause human metabolic diseases, yet several bird lineages convergently adapted to feeding on sugar-rich nectar or fruits. We investigated the underlying molecular mechanisms in hummingbirds, parrots, honeyeaters, and sunbirds by generating nine new genomes and 90 tissue-specific transcriptomes. Comparative screens revealed an excess of repeated selection in both protein-coding and regulatory sequences in sugar-feeding birds, suggesting reuse of genetic elements. Sequence or expression changes in sugar-feeders affect genes involved in blood pressure regulation and lipid, amino acid, and carbohydrate metabolism, with experiments showing functional changes in honeyeater hexokinase 3. MLXIPL , a key regulator of sugar and lipid homeostasis, showed convergent sequence and regulatory changes across all sugar-feeding clades; experiments revealed enhanced sugar-induced transcriptional activity of hummingbird MLXIPL , highlighting its adaptive role in high-sugar diets.