Incorrect Interpretation from GeneTree
Background: In the course of my researching the family history, my grandmother told me that her biological father was not the man who raised her. She was raised by and as a Burkett. However, her mother had told her that her real father was a Davis. Over the next decade, I was able to locate her Davis siblings, whom she had never known. Early in 2003 my grandmother agreed to allow a sample of her DNA to be taken. I had hoped to have her tested with one of her Davis siblings. However, they were not comfortable with the idea at first. In July 2003, my grandmother passed away unexpectedly.
Her Burkett brother agreed to take the test in September after we talked about the family history. The goal was to learn if he was a full sibling or just a half sibling of my grandmother.
In October, GeneTree, sent the results. They were so confusing (and I am a professional statistician!) I called GeneTree to ask them to explain the simple 'yes' or 'no'. Were they full siblings or not? The reply was "yes, they are full siblings". Although these results were counter to what I had expected, I took them as gospel. Surely a company whose sole purpose is to provide such answers would be able to interpret their own conclusion! They were wrong.
Here is a copy of their conclusion:
"the data indicates a greater likelihood of a half-siblingship, there is a
very high probability that Burkett and Miller are full-siblings" --
translation in 2003: they are more likely to be half siblings than full
siblings.
-- translation in 2004: Oops you say the results seem wrong? Oh, they are
more likely to be full siblings than half siblings.
As I uncovered more and more in my genealogical search it became increasingly difficult to accommodate the 'full sibling' conclusion. I called GeneTree again in June 2004, only to be told the opposite. Burkett and Davis were "not full siblings".
Since only GeneTree had my grandmother's DNA and she was no longer living I was hostage to them for any future testing of her DNA. In August, 2 Davis brothers agreed to be tested. Needless to say it was no small effort to gain the confidence of both of these participants, who were both in their 80's.
The results, Davis and my grandmother were half siblings. Therefore, Burkett and grandmother were also half siblings.
Genetree claimed to have tested 33 loci, however only provided results for 14. When I requested a copy of the results for all 33 results they refused.
They are the only ones I know of who offer the test. I hope that either other, more professional, companies will offer this test or that Genetree will develop a higher caliber of customer service and reliable results.
Conclusion: The value of any DNA testing depends, in part, on the integrity of the testing company. If they show a willingness and pattern of getting things wrong, their results are worthless. Unfortunately that has been my experience with Genetree.