In a recent study by Proceedings of the National Academy of Sciences of the United States of America (PNAS), recent research has concluded that the mitochondria (the powerhouse of our cells) can come from both our parents and not simply our mothers. PNAS concluded that, in multiple families, mitochondria from the father’s sperm was able to pass through children over various generations. This new information could lead to better treatment of mitochondrial disorders and even expand our knowledge over the “mitochondrial Eve”.
The mitochondria are able to power our bodies through converting sugars, fats, and proteins that we eat into molecules our cells can use to function. Knowing this, when something goes wrong the result is often grave, generating lifelong problems or even death of babies that have been affected in the womb. Every person with a mitochondrial disease is affected differently, MELAS syndrome begins in early childhood and causes seizures and dementia. Another, Kearns-Sayre syndrome, can result in problems with sight and hearing which can leave a person blind and deaf.
Mitochondria sit separately inside of cells and have their own DNA, different from the cell’s main DNA in its nucleus. They reproduce themselves and move from each generation by accompanying the egg. During fertilization, the father’s sperm transfers his DNA into an egg, however, only a few or none of the sperm’s mitochondria get in. Even if they did, the egg still has special mechanisms designed to destroy them. This new research that PNAS conducted has concluded that, in a few families, the mitochondria from the father was able to enter the egg without getting destroyed. Sometimes the DNA from the father would be more apparent as the fertilized egg grew into an embryo, even more than that of the mothers. Unfortunately, they are not sure how some father’s mitochondria were permissible in the egg yet.
Since even tiny changes can be fatal when a human’s mitochondrial DNA is altered, this can help us study distant ancestors and other people from our ethnic group (we learned this in class too!). However, all of this work has been based on the fact that the mitochondria were passed down from the female line only, and we now know it could be from either parent.
Considered the most significant implications of these findings, we could now produce better treatments because of this new understanding of how the mitochondria are passed on. It could possibly encourage properly functioning mitochondria to multiply inside a fertilized egg at the expense of broken ones as well. The downfall of all of this is how controversial it is to do any of these treatments. Since these treatments would involve influencing someone’s DNA in a way that would be inherited by further generations. However, a Chinese researcher recently gene edited two babies successfully, so maybe, depending on the outcome, this could allow testing treatment on a person’s mitochondria.