Twins are really cool and in this newsletter, we’re going to tell you all about how twins are formed and why they give us so much insight into ourselves. There are two types of twins, identical and fraternal. Identical twins share 100% of their genes and are literal copies of each other (genetically speaking). Fraternal twins share 50% of their genes; this is the same as regular siblings except fraternal twins share a womb before they’re born.
The Fertilized Egg
Fraternal twins come from two different eggs and two different sperm cells. Usually, during ovulation, only one egg is released from an ovary. In the case of fraternal twins, two eggs are released both of these eggs are fertilized. Basically, instead of having two pregnancies consecutively, the mother has two pregnancies concurrently. Women who undergo IVF (in vitro fertilizer) can sometimes have fraternal twins or even triplets because multiple fertilized eggs are put into her uterus in the hopes that one will implant.
Identical twins give us great insight into what behaviors, diseases, and life processes are genetic and which are more influenced by lifestyle. Since identical twins share the same environment in utero (before they were born), they have pretty much eliminated any variables that may influence a study. Of course, it’s important to keep in mind that twins aren’t exactly representative of the general population since they’re not a random sampling. The results of the studies are interesting though!
One study looked at the effects of aging in identical twins. They found that, surprisingly, aging has more to do with lifestyle choices and habits than it does with genetics. While this isn’t a smoking gun, it does add another piece of evidence to the idea that the choices you make can make a difference in the long run and your fate isn’t decided by your genes.
Eating Your Roommate
There’s an interesting phenomenon that happens sometimes and it’s called twin resorption or vanishing twin. This happens when one twin dies in utero and is reabsorbed or eaten by the other twin. When this happens to fraternal twins, the surviving twin becomes a chimera. Chimeras are organisms that possess two sets of DNA. In the case of twin resorption, the person has his/her own DNA and his/her twin’s DNA.
Not A Twin? You Can Get One From Us!
We’re not all so lucky to be born a twin, but if you’re fascinated by twins or are one-half of a twin, then we’ve got the science jewelry for you! Our twin fetus necklace shows these roommates in the womb, nicely tucked away. Purchase this piece for yourself, for your twin, or for a friend who feels like a twin to you. This piece also makes a great gift for IVF technicians, fertility doctors, OBGYNs, and twins.
written by Science with Evie