Convergent gene losses illuminate metabolic and physiological changes in herbivores and carnivores

Significance Mammals repeatedly adapted to specialized diets, including plant-based diets for herbivores and meat- or insect-based diets for carnivores. Apart from consuming diets with different nutritional compositions, obligate herbivores and carnivores differ in other aspects, such as the time spent feeding, regularity of pancreatic juice secretion, exposure to toxic plant-derived compounds, and gut microbiome diversity. To better understand how diet-related changes evolved, we performed genome-wide screens for convergent gene losses that happened preferentially in herbivores or in carnivores. We discovered repeated losses of genes involved in fat digestion, pancreatic juice secretion, glucose homeostasis, appetite regulation, detoxification, and gut microbiome diversity. Our results reveal genomic changes associated with dietary specialization and illuminate metabolic and physiological changes in herbivorous and carnivorous mammals.