Genealogy from the perspective of a member of The Church of Jesus Christ of Latter-day Saints (Mormon, LDS)

Friday, July 1, 2016

DNA and your family tree

One of my friends related that he had recently obtained a DNA test from one of the major genealogical DNA testing companies. He was very surprised to learn that he had a percentage of Pacific Islander genes. He was moderately familiar with his "genealogy" but had never encountered any family tradition or research that showed a connection to the South Pacific. Now, the fact that the DNA test showed a potential relationship is an interesting fact, but without making a connection to a family member or doing some research to establish the basis for the finding, the information is merely interesting.

Recently, the vast online family tree program,, added DNA test results integration with its partner Family Tree DNA. As the blog post from explained:
DNA will enhance the World Family Tree by separating fact from fiction: it will help people confirm family relationships and will highlight situations where the documented genealogy does not match the biological evidence presented by DNA. DNA results will also be used for matching, in order to discover previously unknown relatives. Geni's World Family Tree will then allow users to establish and visualize the precise family tree connection with relatives found by DNA matching. 
Users can add three types of DNA tests to Geni’s World Family Tree: Y-DNA (from the Y chromosome, which is passed down from father to son), mtDNA (mitochondrial DNA, which is passed down from a mother to her children), and autosomal DNA (from all ancestors, pertinent for matching within the last five generations). DNA results can be automatically inferred by Geni from relatives across the family tree; by having a small percentage of the Geni users tested, a great deal of information on the World Family Tree can be verified.
Had my friend already taken advantage of one of the large online family tree programs, such as, he might have had some explanation for the surprising DNA results. It is very likely that as people obtain DNA testing, they will eventually connect themselves to more and more of their own family members. But from my own standpoint, I have been doing extensively documented genealogical research for years. DNA testing could possibly illuminate some of the more difficult to identify relationships, but not without concurrent substantiating research from other lines. The expectation is that with well documented research by many people contributing to family trees such as, eventually, the documentation and relationships will be clarified.


  1. One thing I have wondered about with reports such as from your friend, is why do people always seem to assume DNA testing is correct?

    How many times have companies made "exciting announcements" like Ancestry did this past April in their blog:

    "We’ve been refining and expanding the science behind DNA matching to find your relatives. And we’ve got some exciting improvements coming your way soon.

    "These advancements are expected to deliver more-precise predictions of whom you are related to,...

    Of course, we can’t make your list of DNA matches more accurate without removing some of the less-accurate ones." (

    It's very possible that your friend's unexpected South Pacific genes will vanish with the next improvement in testing results from whatever company he did the test with.

    1. Your response goes to the heart of the issues raised by an increased reliance on DNA testing as a solution to genealogical problems. I don't think any of the companies claim 100% accuracy.