Summary: Researchers report the ability to use sugar as food varies strongly between closely related species. The study identifies a genetic basis for this variation and could shed light on how human populations with different dietary histories may respond differently to modern, sugar rich diets.
Source: University of Helsinki.
Diet choice of animal species is highly variable. Some are specialists feeding only on one food source, such as a sugar-rich fruit or protein-rich meat. Other species, like humans, are generalists that can feed on different kinds of food sources.
Because of these differences, animal species ingest different amounts of macronutrients, like carbohydrates and amino acids. It is conceivable that the metabolism has to match the diet choice of each species. However, we understand poorly the evolution of animal metabolism – what are the underlying genetic changes and how these changes define the optimal nutrient composition for a given species.
The research group led by Associate Professor Ville Hietakangas at the University of Helsinki have studied the evolution of metabolism by using two very closely related fruit fly species. The first one of them is a generalist, Drosophila simulans, which feeds on varying fruits and vegetables, which typically contain a high amount of sugars. The second one is Drosophila sechellia, which has specialized to feed on one fruit, Noni, Morinda citrifolia, which has low sugar content.
“We found pretty dramatic metabolic differences between these species. D. sechellia larvae, that are not exposed on sugar in nature, were not able to grow when placed on a sugar-rich diet, while D. simulans had no problems handling dietary sugar,” explains Hietakangas.
The close relatedness of the fruit fly species allowed the scientist interbreed the species, to make hybrids that were largely genetically like D. sechellia, but contained those genomic regions of D. simulans that were needed for sugar tolerance.
“The ability to analyze hybrid animals was the key advantage of our study. This way we could not only rely on correlating the findings but were able to identify genetic changes that were causally important. We also could tell that sugar tolerance comes with a cost. D. simulans and the sugar tolerant hybrids survived poorly on a low nutrient diet. This suggests that D. sechellia has evolved to survive on a low nutrient environment, which has required rewiring the metabolism in a way that has made feeding on high sugar impossible,” says Hietakangas.
This study opens up many interesting questions, also related to humans. In the future, it will be interesting to explore whether human populations that have different dietary histories, for example experiencing extremely limited nutrition for many generations, may respond differently to modern diets rich in sugars.
Source: Ville Hietakangas – University of Helsinki
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is adapted from the University of Helsinki news release.
Original Research: Open access research for “Natural variation in sugar tolerance associates with changes in signaling and mitochondrial ribosome biogenesis” by Richard G Melvin, Nicole Lamichane, Essi Havula, Krista Kokki, Charles Soeder, Corbin D Jones, and Ville Hietakangas in eLife. Published Noember 27 2018.
doi:10.7554/eLife.40841
[cbtabs][cbtab title=”MLA”]University of Helsinki”Shedding Light on the Evolution of Metabolism.” NeuroscienceNews. NeuroscienceNews, 3 January 2019.
<https://neurosciencenews.com/metabolism-evolution-10421/>.[/cbtab][cbtab title=”APA”]University of Helsinki(2019, January 3). Shedding Light on the Evolution of Metabolism. NeuroscienceNews. Retrieved January 3, 2019 from https://neurosciencenews.com/metabolism-evolution-10421/[/cbtab][cbtab title=”Chicago”]University of Helsinki”Shedding Light on the Evolution of Metabolism.” https://neurosciencenews.com/metabolism-evolution-10421/ (accessed January 3, 2019).[/cbtab][/cbtabs]
Abstract
Natural variation in sugar tolerance associates with changes in signaling and mitochondrial ribosome biogenesis
How dietary selection affects genome evolution to define the optimal range of nutrient intake is a poorly understood question with medical relevance. We have addressed this question by analyzing Drosophila simulans and sechellia, recently diverged species with differential diet choice. D. sechellia larvae, specialized to a nutrient scarce diet, did not survive on sugar-rich conditions, while the generalist species D. simulans was sugar tolerant. Sugar tolerance in D. simulans was a tradeoff for performance on low-energy diet and was associated with global reprogramming of metabolic gene expression. Hybridization and phenotype-based introgression revealed the genomic regions of D. simulans that were sufficient for sugar tolerance. These regions included genes that are involved in mitochondrial ribosome biogenesis and intracellular signaling, such as PPP1R15/Gadd34 and SERCA, which contributed to sugar tolerance. In conclusion, genomic variation affecting genes involved in global metabolic control defines the optimal range for dietary macronutrient composition.
