Do Twins Share the Same DNA?
Do Twins Share the Same DNA?
When you look at twins—specifically identical twins—it is easy to assume everything about them is alike. They may bear the exact same physical traits, personality, and mannerisms.
You may also assume their DNA is absolutely identical…but is this true? Many people have been left wondering whether twins truly do share absolutely everything in common based on their DNA.
But do twins share the same DNA? Here is the information you need to know:
How Can Twins Happen?
First and foremost, there are two types of twins:
· Identical
· Fraternal
Identical twins
Identical twins can also be referred to as monozygotic twins. Identical twins result from the fertilization of one single egg by one single sperm. The egg then splits into two separate parts.
Identical twins share identical genomes. They are also always the same sex as the other.
Fraternal twins
Fraternal twins can also be referred to as dizygotic twins. Fraternal twins result from the fertilization of two separate eggs with two different sperm.
The pregnancies will occur at the exact same time. Fraternal twins share half of their genomes with one another—like other siblings. These types of twins may also be opposite sexes and may not resemble one another.
Do Twins Have the Same DNA?
Being that there are two different kinds of twins, there are two different answers.
Identical twins
Until recently, it was thought that identical twins share the exact same DNA. They first started as one egg, which is its own DNA. The egg then split into two. The DNA is the exact same between the two eggs as they are both derived from the original egg.
With developing research, scientists have revealed that slight differences may occur between identical twins. This can include:
· Health
· Personality
· Physical characteristics
Nature Genetics conducted a study that showed 15% of its identical twin participants had a “substantial number of mutations” that were given to one twin and not the other. Nearly 40 more pairs of identical twins possessed over 100 genetic mutations, while the others showed no mutations. Environmental factors—including nature versus nurture—were cited as being responsible for the differences and mutations.
Fraternal twins
In short, no, fraternal twins do not share the exact same DNA. They share 50% of their genomes such as other siblings. This is why they do not mirror one another.
Since fraternal twins happen from having two pregnancies at the same time, they are not considered identical as they are from two separate eggs versus one egg that splits. They will, however, have genes in common with one another from both their mother and father.
Bottom Line
New science has determined that identical twins do share up to 99% of DNA with one another. The 1% falls to genetic mutations that can be influenced by nature and nurture—or their environment and upbringing.
Fraternal twins can be considered siblings that were born at the same time. Due to the fact they were conceived with two separate eggs, they do not have the same DNA but do share 50% of the same genes.
