The only reservations I had about last nights episode was the language used when presenting DNA results. When Rebecca Lobo was told exactly which line her Ashkenazi admixture came from, I thought Dr. Gates was over stepping a little. It does seem, most likely, she got the admixture from the stated line (an Austrian line). Documentary evidence leads to that belief too, but you never know for sure unless you test more family members. Working with my DNA admixture results I was fooled a few times when trying to make an educated guess about where an admixture came from. It wasn't clear to me that I was wrong until I had more relatives tested. Ashkenazi is one of the admixtures which is easy to identify. The percentages are tricky though. She is predicted to be 10% Ashkenazi, so Dr. Gates surmised from that percentage that this came down from a particular great-grandparent based on rough inheritance percentages. Since inheritance is random, the only percentages we know for certain are that we inherit 50% of our DNA from each parent, after that generation there can be more variation in inheritance. For instance last week we learned that someone's father was substantially Ashkenazi according to available documents. This person's DNA results came out to be 12% percent Ashkenazi. So if we based our prediction of where this DNA came from we would guess farther back in time than parent based on estimates using average inheritance. Admixture percentages can fool you, and you can get admixture from more than one line. There is no way to say with 100% confidence which ancestor you got a particular admixture from, unless you test many relatives. When I watched this show before I got involved in autosomal testing and I heard, for instance, Dr. Gates say that a tradition of Native American ancestry was wrong based on DNA testing I believed that to be true. Since then I've learned that we don't inherit DNA from all of our ancestors; so it's possible a family tradition of Native American ancestry may be true even if you don't see it in your DNA results. So it's still possible Billy Jean King has some Native American roots?
Dr. Gates did use the word "suggests" when talking about results sometimes. The word "suggests" is often the best word to use when talking about results.
I'm convinced that Derek Jeter is descended from the family that owned his family. Y tests are more reliable than autosomal (autosomal testing is most reliable for close relatives). He is also most likely descended from the slave owner as stated. However, it's not 100% positive. I believe Dr. Gates did say that this connection was most likely the case, but didn't say 100% certain like he did with Rebecca Lobo. You can't look at DNA and say it came from a particular person or line with 100% certainty. With Y DNA you can only say you are definitely related or definitely not related using the test. It would be tricky to do a TV show and explain the intricacies of DNA testing. The general public probably isn't interested in learning about predictions either. They want to hear about definite conclusions. They might come away disappointed if they took a test after watching some of these episodes? Otherwise, I love the show and listen to the DNA test results with great interest.
Another point of interest is the DNA tests the guests took were blood tests. I wonder which company they used?
I was so happy to hear from someone in the Brenneman family line at Facebook. He and some of his family members had their DNA tested. He, his sister and father were low confidence matches at AncestryDNA. We compared at GEDmatch and I found out he shares a 7 cM segment with my Mom. His sister and father shared an 8.9 cM segment in the same place. I would say low confidence is a good prediction based on the amount of DNA we share. I'm always interested in comparing at GEDmatch with AncestryDNA matches because the phasing process that produces the confidence levels doesn't always work. I'm very interested in the Brenneman line. I've found trees connecting my family to this one, but I can't find documentary evidence? Hoping DNA will help?
|I'm hoping these segment on Chromosome 16 are from Brenneman line?|