Twin Zygosity Testing Revisited
With the announcement of the discovery of “semi-identical” twins last week, now is an excellent time to review Beta’s twin zygosity test services.
Doctors often identify twins based on the number of placenta present at birth, but sometimes this is overlooked. The twin zygosity test offered by Beta is a useful tool for identifying identical and fraternal twins based on their genetic similarities.
Identical twins result from a mother’s egg being fertilized by one of the father’s sperm and then splitting early in the development of the fetus. In this process, the two embryos that form will develop into two siblings that are essentially genetically identical. They will also share the same placenta. When comparing the genetic profiles of the two siblings, they will match at every marker.
Fraternal twins, who are more common than identical twins, arise from the union of two of a mother’s eggs with two separate sperm from the father. The fertilization of the two eggs typically occurs at the same time, however it is possible for one egg to be fertilized after another. In this way, fraternal twins can in fact have two different fathers. Fraternal twins use separate placentas and are as genetically similar as non-twin siblings.
The newly discovered semi-identical twins are combinations of identical and fraternal twins. They form from the same egg, but the egg is fertilized by two separate sperms, so the twins end up having identical maternal genetics but different paternal genetics. This situation is quite rare and can be accompanied by congenital conditions easily identifiable by medical doctors.
If you or your relatives are twins, you may consider taking a Twin Zygosity Test. To learn more about or to order a Twin Zygosity Test, call us at 1-800-798-3810 today.
This entry was posted
on Wednesday, April 4th, 2007 at 12:25 pm and is filed under Home Paternity Tests.
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