Meeting Abstract
For decades, carotenoids-based coloration has been one of the most extensively studied ornamentations in birds, they are responsible for many of those yellow, orange and red colors in birds’ feather, beak, and skin. Carotenoid-based coloration, especially red coloration, is also an important criterion for mate choice in many different taxa including birds, and it’s one of the most classic examples of honest signals in sexual selection. Unlike yellow carotenoids, which can often be obtained directly from the diet, red ketocarotenoids are usually not readily available in songbirds’ diet and must be generated through metabolic conversion of those yellow dietary carotenoids. Despite the wide interest and tremendous effort on understanding the function of these red pigments, the site of carotenoid metabolism remains uncertain and contentious. In previous work, we’ve located a high concentration of ketocarotenoids in hepatic mitochondria extraction from house finch (Haemorhous mexicanus), indicating a potential link between mitochondria and ketocarotenoid conversion. In this study, we successfully separated matrix and inner mitochondrial membrane from the outer mitochondrial membrane. And by running carotenoid analysis on each of those fragmentations, we found a high concentration of red ketocarotenoids to be inside mitochondria, and most likely on the inner mitochondrial membrane. This work has an important implication for the cellular mechanisms that regulate the production of ornamental plumage coloration as well as the shared pathway hypothesis, which suggests the production of carotenoid pigmentation is intimately linked to core cellular processes like cellular respiration in mitochondria.And this is the very first study reporting submitochondrial location of red ketocarotenoids in animals.
