Dahm Triplets DNA Test
Who Are The Dahm Triplets?
Many people who have heard of the Dahm Triplets know of these three sisters thanks to their modeling career that took off because of the unique genetic anomaly that led to them being identical.
But what many people don’t realize is the Dahm Triplets are an example of how rare it is for identical triplets to occur — and that their existence lets DNA researchers and scientific experts get an interesting perspective on how DNA is shared between siblings (especially those who are considered identical).
The Dahm Triplets — Nicole, Erica, and Jaclyn — were born in 1977, and the 41-year-old sisters have gone on to become celebrities thanks to the unusualness of being exactly identical. So, why are identical triplets so rare? It all has to do with how many eggs are present at conception, and how they may potentially divide into multiple eggs.
Here’s how the division of eggs can lead to multiple births — both fraternal and identical — during the earliest stage of pregnancy.
- Single Pregnancy: In a normal, single pregnancy, a fertilized egg does not split, leading to the birth of just one child.
- Twin Pregnancy: When it comes to twins, there are two routes that conception can take: twins through egg splitting, or twins due to multiple eggs being released from the ovaries at the same time. In cases where just one egg is released and fertilized by one sperm, it’s possible for twins to occur if the egg divides into two eggs. This leads to identical twins who will have the same chromosomes and DNA. Non-identical twins, called fraternal twins, occur when two eggs are released from the ovaries, and they are fertilized by two different sperm.
- Triplet Pregnancy: Triplet pregnancies follow the same path as twin pregnancies. For fraternal triplets, multiple eggs are released by the ovaries and individually fertilized by different sperm. But in exceptionally rare cases, one fertilized egg splits into three different eggs, creating three embryos with the same DNA. This rare feat is what leads to identical triplets.
Statistics on multiple births — twins, triplets and more — suggest that triplets naturally occur in only 1 out of every 8,100 births 1. That means for people who aren’t using fertility treatments, medications, or procedures to get pregnant, the odds of having triplets are pretty slim.
And when it comes to determining if those babies will be identical, the chances become even smaller. In fact, research regarding twin and triplet birth rates spanning nearly three decades and eight different countries published in the Journal of Biosocial Science shows that the odds of having three identical children are so low that it only occurs between 20 and 30 times per 1 million triplet births 2.
Even though the Dahm Triplets look identical and can be difficult to tell apart, many people wonder if they, and all sets of identical twins and triplets, have the exact same DNA. Is it possible for there to be minute genetic differences between the three sisters?
The Dahm Triplets, with the help of news entertainment show Inside Edition decided to take an at-home DNA test to see if this is possible.
What DNA Tests Did The Dahm Triplets Take?
In early 2017, the Dahm Triplets teamed up with Inside Edition and several other groups of identical siblings to test the accuracy of at-home DNA testing kits.
According to Inside Edition, the counsel of a DNA testing expert suggested that any DNA test results for the three sisters should come back “absolutely identical” since they shared the same DNA.
The sisters had their DNA analyzed for two different genetic tests provided by 23andMe, a popular genetics testing company that provides home DNA test kits. The first test was used to confirm that the sisters were indeed triplets. The second 23andMe test run with the sisters’ DNA (collected with a saliva sample) looked to determine their ancestry.
What Were The Results Of The Dahm Triplets’ DNA Tests?
The first 23andMe DNA test — determining if the Dahm Triplets were in fact, triplets — had expected results. The DNA test confirmed that the three sisters were triplets sharing the same DNA.
But when it came to the results of the second test for ancestry, there were some questionable differences among the Dahm Triplets.
While all three sisters were determined to be 99 percent European, the individual breakdowns of different ethnicities varied among the sisters. Nicole Dahm’s DNA was considered 11 percent French and German, though sister Erica’s percentage of this ethnic blend was 22.3 percent.
Even more confusing, the third Dahm triplet, Jaclyn, was considered to be 18 percent French and German. In addition, the sisters also had differences in their results for having Scandinavian ancestry. Nicole’s DNA test results said she was 11.4 percent Scandinavian, while Erica and Jaclyn were both 7.4 percent 3.
In a televised review of their results on daytime medical show The Doctors, the sisters expressed confusion on how the results could differ, and wondered if they each had other minor genetic differences that until this time have gone unnoticed.
Why Were The DNA Test Results Different Between The Dahm Triplets?
It’s not exactly clear why the Dahm Triplets’ DNA results differ. It is possible that obtaining DNA from a saliva sample could impact results, especially if directions for collecting the sample aren’t followed properly.
Still, further research into the genetic similarities and differences between identical twins, triplets, and quadruplets suggests that slight genetic differences may be possible, even though long-standing belief has been that identical siblings share the exact same DNA 4.
According to researchers at the University of Alabama at Birmingham, studies of identical twin DNA shows that there are some genetic differences between identical siblings. According to this research, genetic scientists are beginning to believe that twins and identical siblings have more genetic differences than early research has revealed 5.
What Did Ancestry Say About The DNA Test Results?
While the Dahm Triplets used a DNA test from 23andMe, two other sets of identical siblings also helped Inside Editions test of at-home test kits.
Test company Family Tree DNA told Inside Edition that it had plans to improve its testing algorithms and methods following differing results among other identical siblings. An Ancestry DNA test was used for another identical sibling test, though Ancestry DNA did not make a response to the television show’s testing.
As for 23andMe, the company that sells the test the Dahm Triplets utilized, a spokesperson told Inside Edition that the differences could be based upon how the results were interpreted. Because the company offers results on a “sliding confidence scale” that ranges from 50 to 90 percent, people can explore their potential ethnic backgrounds based on the testing company’s confidence in how accurate the results are 6.
“The higher the confidence level chose, the less specific the result can be as to the region or country of the person’s ancestry,” Inside Edition reported.
What Can We Learn About Home DNA Tests?
If there’s any major takeaway from seeing the Dahm Triplets’ at-home DNA test kit results, it should be an understanding that modern DNA testing isn’t 100 percent spot on when it comes to determining a person’s ethnicity or ancestry.
There are many factors for this; according to the Scientific American, each genetic testing company has its own database and algorithms for determining what ethnic group a person may belong to 7. This means that results for the same person can vary between different genetics testing companies.
And further, how we interpret DNA and testing results is an ever-evolving process.
If you’re interested in taking a DNA test for ancestry and ethnicity information, you should know that the results can point you in the best direction for tracing your family’s heritage, though tests that give a percentage breakdown of different ethnic blends shouldn’t be considered 100 percent accurate. Still when it comes to determining if two people share enough DNA to be related, home DNA test kits are remarkably reliable.
And, if you’re considering taking a DNA test to learn more about a health condition, you can feel confident analysis of your DNA can give clear answers to potential health risks and factors.
- Expecting twins.
motherforlife.com. 2019. ↩
- A comparative study of zygotic twinning and triplet rates in eight countries, 1972-1999.
Imaizumi Y. J Biosoc Sci. 2003 Apr. ↩
- Identical Triplets Take A DNA Test, But The Unsettling Truth Is Revealed.
Lionel Arkin. Published on Aug 16, 2018. ↩
- Identical Twins Are Genetically Different, Research Suggests.
Tia Ghose. Live Science. November 9, 2012. ↩
- Subtle Differences in DNA of Identical Twins May Help Diagnose Disease.
The University of Alabama at Birmingham. 2008. ↩
- How Reliable Are Home DNA Ancestry Tests? Investigation Uses Triplets to Find Out.
Inside Edition. 2017. ↩
- How Accurate Are Online DNA Tests?
Adam Rutherford. October 15, 2018. ↩