Twin Zygosity DNA Tests
A Twin zygosity test determines definitively whether twins are identical or fraternal. Using ultrasound examination of the placenta, an OB-GYN doctor may be able to tell whether twins are identical or fraternal. After twins are born, a pathological examination of the placenta can also be conducted to determine zygosity. However, scientists recommend DNA testing to determine zygosity, as studies have revealed that either method is not 100% accurate. Occasionally when medical records regarding zygosity is lost, or unavailable, or when the twins physical characteristics vary and are different as they grow a zygosity test will reveal whether they are actually identical or fraternal. Only a twin zygosity test that compares the twins DNA profiles to see whether they match exactly can conclusively answer that question: an exact match means that the twins are identical.
Identical Twins twins come from one fertilized egg, known as a zygote. The zygote, which usually develops into one child, grows and divide early in development stage to form two embryos which results in dentical twins. Because the twins come from one egg and one sperm, they have exactly the same DNA.
Fraternal Twins on the flip side of this Fraternal twins develop when there are two different eggs in the mother’s womb that are fertilized by two different sperms. Fraternal twins will not have exactly the same DNA, although like other siblings, they can be expected to share some of the DNA they inherit from both parents
The results of a twin zygosity test may be used to satisfy one’s curiosity and assist in health problems for the twins later in life or as they grow up. For example, if one twin twin should ever need an organ or tissue transplant the other twin would be a perfect donor as they share identical DNA.
