DNA Testing and Twins

From the moment some twins are born, parents are certain of one thing—they aren’t identical! Perhaps they have different hair or skin colors, or perhaps, like my twins, one has a distinctive hereditary mark (a cleft chin) and the other does not. But many parents of twins are uncertain if their twins are identical or fraternal. In these cases, performing a simple, painless DNA test can give parents and twins the answer.

DNA testing has revolutionized the world in many ways. These tests have made it possible to prove or disprove paternity in child support and/or custody battles; DNA testing has proven the innocence or guilt of suspects in criminal cases. DNA tests can also help find matches for those who need organs or other body tissue transplants.

One interesting project involving DNA is called the DNA Ancestry Project. By studying genetic markers from around the world, scientists can now look at your DNA and tell you where your ancestors came from. Another portion of the project can match your DNA with family surnames, helping trace your genealogy. For more information on this project, see the link at the end of the article.

So, how does this all relate to twins? Well, if your twins are identical, much of the DNA is identical. The reason for this is that monozygotic (identical) twins occur when one fertilized egg splits into two babies. If your twins are fraternal, they won’t share as much of their DNA “footprint”—in fact, their DNA will only be as similar as any other pair of siblings who are born years apart.

There are many companies that offer DNA testing for twins. The tests can be ordered over the internet or the phone. The cost ranges from $150 to $250. Very few health insurance companies cover zygosity testing, as it is usually an unnecessary procedure. However, it might be worth a call to your health insurance provider, to see if the test might be partially covered or offered by your pediatrician.

The tests themselves are quite easy and painless to perform, even on small babies. All that is needed is a “cheek swab”—essentially, a quick swipe of the inside of the cheek with a cotton swab. After each twin is swabbed, the parent simply packages up the swabs and sends them back to the company, where they are tested for zygosity. In a few weeks, sometimes less time, the company can tell you if your twins are identical or fraternal.


Twin DNA Tests:
https://genetree.com/relationship/twins.php
https://www.gtldna.com/twinzygosity.html
https://www.genelex.com/paternitytesting/paternitytestinginformation.html

DNA Ancestry Project: https://www.dnaancestryproject.com/




Check out this related article
The Difference Between Monozygotic and Dizygotic Twins