Scientists create large library of mitochondrial DNA mutant models

Some of your most important life partners are the mitochondria that power all your cells. You and these little cellular powerhouses are in a 1.5-billion-year-old evolutionary relationship-but mitochondria brought some baggage. Mitochondria brought their own DNA with them when they joined with the bigger, more complex cells so long ago, and today that mitochondrial DNA influences human health.

Salk Institute scientists are asking what those influences are, and their latest study unveils a new biological platform for studying mitochondrial DNA in physiology, adaptation, disease mechanisms, and therapeutic development. Already, they have used the platform to generate a library of 155 mitochondrial DNA mutant cell lines and reveal correlations between mouse development and mitochondrial function. The platform, library, and findings will accelerate therapeutic development for mitochondrial disorders, as well as help scientists treat mitochondrial dysfunction in other diseases and conditions like cancer or aging.

The study was published in Proceedings of the National Academy of Sciences on April 10, 2026, and was funded by both federal research grants and private philanthropy.

"Mitochondrial DNA accumulates mutations at a high rate, and more than 260 inherited disease-causing mtDNA mutations have been identified in humans," says senior and co-corresponding author Ronald Evans, PhD, professor and director of the Gene Expression Laboratory and holder of the March of Dimes Chair in Molecular and Developmental Biology at Salk. "Until now, a lack of models representing this diversity has limited mechanistic insight and therapeutic development. Our new platform will allow scientists to investigate mitochondrial DNA variation in health, disease, and evolution, which will enable therapeutic innovation for mitochondrial disorders."

What are mitochondrial disorders?

Mitochondrial DNA does the extremely important job of creating the proteins needed for energy production-but it also has an especially high rate of mutation, and those mutations can accumulate thanks to inefficient repair mechanisms. Because mitochondria are essential parts of every cell, their dysfunction can lead to body-wide dysfunction, with especially devastating impact on high-energy organs like the brain and heart. Without enough power in your cells, symptoms like migraines, muscle weakness, and loss of hearing or sight can begin to manifest.

The chronic and broad impact of mitochondrial dysfunction makes it especially important to study. Trying to pinpoint the outcome of specific mitochondrial DNA mutations was a slow, arduous process for many years. Researchers would create mouse models one-by-one with different mitochondrial DNA mutations, with just one model sometimes taking years. This was a problem Salk staff scientist Weiwei Fan, PhD, noted early in his scientific career and set his mind to as a PhD student.

"This new work is all building off an original platform I generated during my PhD," says Fan, first and co-corresponding author of the study. "That platform was inefficient-it took a long time to generate just one mitochondrial DNA mutant. With some technological improvements and modifications, this new platform is much more efficient and can create dozens of mutants with far greater ease."

What do biological models teach us?

The new Salk model is a scalable, stem-cell-based platform creating mice with mutations to their mitochondrial DNA. Once one of these mice is established, researchers can investigate the specific symptoms of their specific mitochondrial DNA mutation and the mechanisms by which those symptoms arise-insight that can be used to design targeted therapies down the line.

The platform starts with a protein, called mitochondrial DNA polymerase, generating randomly mutated mitochondrial DNA. That mutated mitochondrial DNA is then transferred into stem cells, which can be integrated with mouse embryos to create mice for study.

Using this platform, the Salk team generated a library of 155 mitochondrial DNA mutation cell lines, each with its own distinct impact on mitochondrial performance. They then used that library to validate that the cells could be used to generate mice with single mitochondrial DNA mutations. These mice allowed them to find a strong correlation between mitochondrial function and early embryonic development, suggesting a baseline energy level is required for normal development.

How does this new resource change mitochondrial disorder treatment?

"Our library is a huge milestone and is very diverse, with a scale of diversity similar to the known human disease-causing mutation diversity of around 260," says Fan. "And with this collection of mutant cells, we can not only look at inherited mutations but also at ones that occur based on other stresses like environmental cues or aging."

The new platform and library are cracking open the world of mitochondrial DNA. With the ability to generate mitochondrial DNA mutants more rapidly, therapeutic development for mitochondrial disease and dysfunction will come more rapidly, too. The mouse models are already a huge step forward for the field, but the researchers are also eager to move into human models in a more human-relevant context.

"The majority of human diseases come with or cause mitochondrial dysfunction," says Evans. "Progress in this field has been limited, but this new platform is going to fuel so much important research that points to therapeutic approaches to combat mitochondrial diseases, as well as diseases or conditions associated with mitochondrial dysfunction like cancer or aging."

Other authors and funding

Other authors include Lillian Crossley, Hunter Robbins, Mingxiao He, Yang Dai, Morgan Truitt, Annette Atkins, and Michael Downes of Salk, and Tae Gyu Oh of Salk and the University of Oklahoma.

The work was supported by the National Institutes of Health (P01HL147835, DK057978, DK120515, 1R21OD030076, CCSG P30CA23100, CCSG P30 CA014195, CCSG P30 CA014195, P30 AG068635), Department of the Navy, Office of Naval Research (N00014-16-1-3159), Larry L. Hillblom Foundation, Inc. (2021-D-001-NET), Wu Tsai Human Performance Alliance, Henry L. Guenther Foundation, and Waitt Foundation.