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You inherit mitochondrial DNA solely from your mother
Your genes are determined at conception, with one copy of each gene being transmitted to you from your mother and one copy from your father. Unlike nuclear DNA, which is inherited from both parents, mitochondrial DNA is inherited specifically from your mother.
What is mitochondrial DNA?
Mitochondrial DNA (mtDNA) is the circular chromosome found inside the mitochondria, which are cellular organelles, located in the cytoplasm and responsible for the cell's energy production and many other metabolic functions.
Unlike the DNA that is inside the nucleus of the cell, the DNA inside the mitochondria are small, circular, and made up of only about 16,500 base pairs. It encodes different proteins that are specific to the mitochondrial pathways for producing energy.
Why is mitochondrial DNA inherited only from your mother?
In the majority of multicellular organisms, mtDNA is maternally inherited. Reasons for this are believed to include the following:
- Simple dilution (an egg contains on average 200,000 mtDNA molecules, whereas a healthy human sperm contains only on average 5 molecules)
- Degradation of sperm mitochondria in the male genital tract or in the fertilized egg
- Failure of sperm mtDNA to enter the egg, at least in a few organisms
During sexual reproduction, the mitochondria of sperm are usually destroyed by the egg cell after fertilization. As most mitochondrial DNA are located at the base of the sperm's tail, which provides energy for propelling the sperm cells, they are sometimes lost during fertilization.
Your father's mitochondrial DNA is marked with ubiquitin to be selected for later destruction inside the embryo. Fertility procedures such as in vitro fertilization techniques, especially injecting a sperm into an egg, may interfere with this process.
What disorders are influenced by your mother’s genes?
If there is a defect in some of those mitochondrial DNA bases, meaning a genetic mutation, the baby will have a mitochondrial disease.
Mitochondrial diseases involve the inability to produce sufficient energy in body tissues such as those in the brain, kidneys, and muscles. Since mitochondrial DNA is inherited from the mother, it can be helpful in diagnosing genetic disorders.
Traits and diseases that are often inherited from your mother’s genes include the following:
- Weight
- Eyesight
- Aging
- Intelligence
- Hemophilia
- Heart diseases
- Certain cancers (especially cancers of the breast or reproductive organs)