Recently, scientists have found evidence that biological identical twins may not be as identical as we thought. In fact, their personality or emotions, and memories aren’t different, but their actual DNA is different. Today, we will talk about what are identical twins and why they are identical, why their DNA might be different, and why that’s important. Now let’s get this ball rolling.
First of all, what are identical twins, and what makes them different than regular twins? Well, there are two major types of twins, along with some other types like Siamese twins; Fraternal twins, which are the most common type, and Identical twins, the much less known type. Fraternal twins are born when two different eggs of a woman are fertilized by two different sperms, and so two different kids start to grow with different qualities, sharing different qualities and 50% identical DNA, just like regular siblings. But, identical twins, also known as monozygotic twins, occur when one egg of a mother gets fertilized by one sperm, and that fertilized egg actually splits in half making two fertilized eggs. Because the egg was fertilized before it split, it shares the same DNA.
Next, how would identical twins’ DNA be different? They were fertilized, and then they split, so how could they be different? In order to know, we need to take a close look at the study that discovered this. In Iceland, scientists studied the genetic makeup of 381 twins. They found that only 38 twins had an identical genetic makeup, and 39 twins had over 100 genetic differences. They found the main reasons for this to occur:
- When the embryo split, the two parts didn’t have the same amount of cells, or they weren’t shaped properly, because the line from which the embryo split was uneven and crooked, or a cell or cells split off, and they weren’t enough to form another baby.
- Early in development, after the split, something caused movement of the cells, causing something to be knocked off or misshaped
- After they were born, differences in each twin’s environment caused a domino effect, to make big genetic differences.
Finally, why is this important? Monozygotic twins are used to studying things like vaccines, medicine; and they are used to study whether particular traits, diseases, or conditions result from genetics or from environmental influences. Because of this study, scientists are going to have to do much more in-depth research on these studies, and take everything with a grain of salt.
In the end, we need to take this seriously and remember that things may look the same from the inside, but in reality, they are very different. I enjoyed writing this post, and I hope you enjoyed reading it!