Are Genes Split 50/50 Between Parents?

Do you share more of your looks and characteristics with your mom or your dad? People often wonder if they are more one parent’s child than the other, or if they are a direct split of both parents. The way genes and DNA are passed on to children is not as simple as it may seem. 

According to genetic research, you carry more genes from your mother than your father. Tiny little organelles that exist within your cells called mitochondria are only received from your mother. Thus, you receive more genes from her. 

How genes are expressed, and the influences of them, are specific to each person. Keep reading to learn more about patterns of inheritance and the traits you receive from each parent.

Mitochondria Has The Answer

The mitochondria that you receive from your mother are like the energy factories of each cell. Mitochondria play a vital role because without them, your cells would not succeed in producing enough energy from food.

Mitochondria are also important in giving our bodies the energy it needs. Tissues, like your brain and muscles, are full of mitochondria and need it to ensure proper functioning.

If you can believe it, mitochondria are nearly 2 billion years old, and once were free-living organisms. Moreover, if you really look closely, you’ll learn that mitochondria are actually an ancestor of bacteria. 

Due to their history, mitochondria actually possess their own genome, referred to as mitochondrial DNA (you may see this referred to as mtDNA as well).

mtDNA is used in DNA tests to understand your family's matrilineal line since, as we have learned, your mitochondria are inherited from your mother. 

Mother's Cells

Even if you are the spitting image of your father, or if you both love the same things and look exactly alike, you are technically more related to your mother than to your father.

So the question is, why do we have different types of inheritance? Additionally, why does one type exclude one parent so completely?

The truth is, this question has eluded evolutionary biologists for many years. They all seem to agree on one thing, though: our inheritance of mtDNA is for a good reason. 

When mtDNA replicates inside the cell, it increases the number of copies over time. The more copies, the more likely some of that DNA will be transmitted when the cell divides.

In plain terms, if all your mtDNA comes only from one parent, then there is less competition within the cells. The mitochondrial genomes are then competing with copies of themselves, making things easier.

If these cells were spending all their time fighting over different types of DNA (like that from your father, grandfather, and beyond), it would be slower to produce and more likely to give off less energy, which is vital for survival. 

That being said, this is just the theory behind the idea of why we get all of our mtDNA from our mother, which seems to make evolutionary sense. We still do not actually know why. 

Patterns Of Inheritance

Even the same two parents with four kids can result in very different DNA outcomes. Each time a child is created, the DNA inherited is dispersed differently.

That’s why if you and your siblings all take DNA tests, you are likely to get some different outcomes.

Think of it this way: 

• Your father can pass 50% of his DNA to each of his children 
• Your father’s DNA is randomly distributed to the child 
• At the same time, the DNA from your grandmother comes into play and gives you a portion of your DNA
• Combine that with your mother and any other DNA you receive from your ancestors, and that results in a totally unique combination of DNA, specific only to you.

There is one exception, however, which are identical twins.

In general, the mixing of DNA is important to keep people healthy, varied, and thriving.

Too much sameness can result in genetic disorders, disease, and other serious consequences.

It's Good To Share, But Not Too Much

So how is it possible that you are the spitting image of your dad, but are more closely related to your mom? Well, your genetic makeup is only part of the answer. 

Genes are essentially turned “off and on,” so which ones are expressed can depend on a variety of factors.

It is possible that certain genes you inherited from dad appear more prominent than others.

Conclusion

While you are technically more closely related to your mother, you inherit DNA from both of your parents.

Your specific combination of genes is totally unique to you. 

Try an mtDNA test if you want to learn more about your DNA from your mother’s side of the family.

Most of the direct-to-consumer kits available today provide insights into your maternal and paternal lines if you are interested in learning about ancestry from both sides of your family. 

Enjoy discovering all the unique characteristics that make you, you!