Mitochondrial Genetic Variation Across Tissues Of The Human Body
Our bodies are made of trillions of cells, and within most of these cells are tiny powerhouses called mitochondria. These mitochondria have their own small set of genetic instructions, separate from the main DNA in the cell’s nucleus. Sometimes, different versions of these mitochondrial genetic instructions can exist within the same cell or tissue, a condition known as heteroplasmy. This study explored how these variations are distributed across different parts of the human body.
Using advanced genetic sequencing techniques, which allow for rapid and detailed reading of DNA, researchers examined many different tissue types from numerous individuals. They discovered that a significant portion of the unique mitochondrial genetic variations were found in only one specific tissue, while a smaller percentage appeared in several, but not all, tissues within the same person. This suggests that these genetic changes often develop anew after a tissue has formed and specialized, rather than being inherited or present from early development.
Interestingly, tissues with cells that divide frequently tended to have more of these unique, tissue-specific variations. In contrast, tissues that require a lot of energy, like the heart, had fewer. The number of these tissue-specific variations also increased with age in some tissues. These findings indicate that our mitochondrial DNA is constantly changing throughout our lives in a way that is unique to each tissue, which could have important implications for understanding various diseases.
Source: link to paper