How Much DNA Comes From Each Parent?

Do you want to learn about how much DNA comes from each of your parents? In this post, find out how much of your DNA comes from mom and dad, and whether one of them gave you more than the other.

Questions like these come up all of the time, especially when a daughter looks more like her dad than her mom. Or, maybe the son looks more like his mother’s side of the family than his father’s relatives.

When we see children that are “spitting images” of either parent, we may wonder if they share more DNA with that parent.

Furthermore, in many cultures, children are given the surname of the father and not the mother. Is it because of our genes that many countries follow this this tradition?

The answer might surprise you!

What percentage of DNA do you inherit from each parent?

The basic answer is that every child inherits an essentially equal portion of DNA from both of their parents. In other words, every person shares about 50% of their DNA with both their mother and father.

The majority of the DNA that we inherit from our parents is contained within our numbered chromosomes, also called autosomes. We have 22 numbered chromosomes and that is where the autosomal DNA from both of our parents is found.

As an aside, autosomal DNA is the most common type of DNA analyzed on DNA tests, such as those offered by Ancestry and 23andMe.

You might notice that a few paragraphs above I used the word “about”. If you noticed that, then you may have already guessed that we might usually share a little bit more DNA than with one parent than the other.

Do you get more genes from your father or your mother? Indeed, if we were to examine all of the genes inherited from parents, one would come out as the clear “winner”.

Do you get more DNA from mother or father?

Both male and female humans share a very tiny percentage more DNA with their mothers than their fathers. This is because most cells in the human body contain about 500 of mitochondrial molecules that were passed down directly from the mother’s maternal line.

Everyone inherits this mitochondrial DNA from their mother, despite their biological gender. Only in a handful of exceedingly rare cases have scientists discovered children sharing mitochondrial DNA with both their father and mother.

The vast majority of us can rest assured that our mitochondria has been stocked with DNA from our mother’s genes. It is also important to mention that mitochondrial DNA is different than the autosomal DNA that you read about towards the beginning of this article.

Mitochondrial DNA is difficult to measure exactly, but estimates of this type of DNA are a percentage of our overall DNA is about 1%. If we inherit half of our mother’s autosomal DNA and share an additional 1% of our DNA with her through sharing mitochondrial DNA, it’s easy to understand how we share a bit more with mom than dad.

If we add in the X-DNA that mothers pass down to both their daughters and sons, which equals roughly about 5% of the total DNA in cells, it tips the genetic scales further in mom’s favor. However, even though you might share more DNA with your mother, it doesn’t mean that you will look more like her or have a similar personality.

What genes are inherited from the father only?

Even though we share slightly more overall DNA with our mothers, there is important DNA that only comes from our fathers. The special genes that we get from our dads are different depending on our biological gender.

As was noted earlier, we have 22 numbered chromosomes. However, everyone has a total of 23 chromosomes.

The 23rd chromosome is what determines our biological gender. If we have two copies of the X-chromosome, we are female; one X and one Y-chromosome, we are male.

Fathers pass down Y-DNA to their sons and X-DNA to their daughters. The result of this is that females will share 50% of their autosomal DNA with their fathers, along with one copy of their X-chromosome.

Males will also share 50% of their autosomal DNA with their fathers, but they will share their Y-chromosome with their dad, too.

Even though Y-DNA makes up about 2% of a male’s total DNA, we still find that the autosomal, X-DNA, and mitochondrial DNA from mom outweighs the DNA from the father.

Where does your parents’ DNA come from?

It is hard to think about our parents’ DNA without wondering exactly where their DNA came from. Our mother and father’s DNA was inherited from their parents, our grandparents, in a similar fashion as described above.

Our fathers inherited autosomal DNA and Y-DNA from their fathers, and autosomal, X-DNA, and mitochondrial DNA from their mothers. Both females and males inherit about 25% of each of our paternal grandparents’ autosomal DNA, along with X-DNA from our paternal grandmother.

Males will also inherit the Y-DNA of their paternal grandfather.

Our mothers also inherited DNA from their parents, but since they are female, they inherited autosomal and X-DNA from their fathers and autosomal, X-DNA, and mitochondrial DNA from their mothers. Males and females will receive about 25% of their maternal grandparents’ autosomal DNA, plus their maternal grandmother’s mitochondrial DNA, which can help trace their direct maternal line.

Conclusion

I hope that this post helped you learn all that you needed to know about how much of your DNA comes from each parent. It’s certainly a fascinating topic, and some of our questions have answers that surprise us.

If you have any questions about something that you read in this post, or if you want to share a story about a misconception that you previously had related to this topic, I would love to hear from you in the discussion below.

Thanks for stopping by today!

Share the knowledge!