Do identical twins share the same DNA?

You may have come across a couple of identical twins with very similar faces and manners. You may have wondered if they are really the same?

Twins of the same egg are often very similar and they often dress similarly (parents or babies wear the same clothes since childhood). At times like that, we can hardly find the difference between them. The same egg twins also tend to be similar in both shape and lifestyle. But do twins also share the same DNA?

Let aFamilyToday Health answer this question!

How is called "identical twin"?

Twins (twins) are homosexual cases in which two children are born after one pregnancy of the mother.

Under normal circumstances, only one egg is fertilized by a sperm and formed a zygote. This zygote develops into an embryo in the mother's womb, from which a baby is born.

However, during early development, an embryo can split into two. After splitting, the two zygotes migrate to the uterus, each of which continues to develop into two individuals. Homozygous twins are also known as homozygous twins because the embryo develops from the same zygote.

Besides twins with the same egg, we also have twins other than eggs (also known as heterozygous twins). In this case, the mother ovulates two eggs at the same time. These two separate eggs are fertilized by two different sperm cells and form two completely different zygotes.

So do identical twins share the same DNA?

Twins of the same egg are fertilized from the same egg and one sperm, and therefore have the same original DNA (genome). However, even if the original DNA was the same, not necessarily their genome would be completely identical. When the zygote splits into two separate embryos, the DNA immediately begins to develop individually for each embryo.

The DNA difference is difficult to detect with just routine tests. If we go through the entire genome of the identical twins, it will be possible to find differences in their DNA. Each person's genome is different and this is true even in the case of identical twins. It's like twins of the same egg that have different fingerprints.

When do identical twins have different DNA?

A person's original DNA can be changed through an external genetic mechanism. Epigenetic mechanisms are regulated and modified by environmental cues such as diet, disease or lifestyle that play an important role in regulating gene "on - off". These mechanisms change the chemical structure of DNA and also affect the activity of certain genes. The DNA of identical twins can vary depending on the environment in which they live. These environmental factors can also influence the twins' appearance.

Twins of the same egg are often considered "copies" of each other. They have a similar genome because they are born from the same egg and sperm. However, their genomes cannot be completely identical.

Thus, even if they are twins with the same egg, they still have differences.