October 6, 2013

Understanding Your DNA Results: Comparison Charts

DNA is the latest genealogy tool and I've had my DNA tested with 3 different companies now (with one more pending). I used Family Tree DNA, 23andMe.com and DNA-me for testing. Since I'm a woman I can only test my Mt-DNA or my Autosomal. I have to leave the Y-DNA tests to a male relative. 

DNA results are not easy to understand and I don't pretend to understand them very well at all. So what I have done is make a spreadsheet of the summary of my DNA results - the Haplogroup I am in, my genetic origins and my percentages of various ethnicities. 

Each test is likely to show different results depending on the number of markers that were tested and the algorithms used to interpret the test. So I expected to find some differences but that is what makes testing with more than one company worthwhile. In fact it's important if you want to understand your DNA in more depth.

Definitions

You also have to do a lot of reading (aka research) to increase your knowledge of DNA testing, the various tests and what the results mean. What I have gleaned (admititily just the tip of the DNA iceberg!) Is this: 

MtDNA - Maternal DNA is passed from mother to child (of either sex) and does not change over the generations. A female testing her MtDNA is testing her female lineage from herself to her mother to her mother's mother and so on. This is the X chromosome

Y-DNA - Paternal DNA tests the Y chromosome which is passed, unchanged, from father to son. Thus if you wish to test for your surname and you are a woman, you must find a male relative with that surname to take the test. Women do not have the Y chromosome (We are XX while men are XY)

Autosomal: Autosomal DNA recombines with every generation and that means the number of markers you share with a common ancestor is halved with each generation. 

Haplogroups: The Haplogroup your DNA indicates you belong to will show your deep roots, your heritage going back thousands of years.  

This is very basic but it's a start to understanding. There's no sense paying money for DNA tests and then just letting the results sit there because you don't understand what was tested or what the results mean.




My DNA Test Results

Here is the chart I've finished which shows the comparison of the 3 companies whose results are in. My 4th company is still running my DNA samples so I don't have that yet.


Family Tree DNA is the one marked as FT DNA. They do not narrow down my ethnic origins as much as 23andMe.com but you can see that they both agree the majority of my ethnic origins are European of some sort. 

DNA-me is the surprise with their finding of a smidgeon of African origin. And their Haplogroup assignment of JT also throws me a bit. I have more research to do to try to understand how that happened. I am pretty sure they didn't test very many markers and the more markers tested, the  more accurate the results.

You can also see that 23andMe.com has both Standard (75% accuracy) and Speculative (50% accuracy) results so I included them. The East Asian was interesting especially when I compared my test results to my brother's. Since his tests include the full Y chromosome testing there are bound to be some differences. And I love that 23andMe.com tests for your percentage of Neanderthal ancestry in your DNA! 

My Brother's DNA Results

For example even though we know we have Native American heritage on my father's side, it does not show on my results with any company. But it does show on my brother's results through 23andMe (but not Family Tree DNA) and on tests that Professor McDonald ran on my brother's Family Tree DNA raw data. Again this points out the importance of testing with more than one company. 



You can see that testing my brother's DNA confirmed our Native American heritage and the Asian heritage shown for me in both 23andMe and DNA-me testing. The big surprise was the Ashkenazi in his speculative results. It's important though to note that these results are only considered to have 50% accuracy. They may be correct but they are equally likely to be wrong. 

DNA Matches

I've also been studying and reading about how to compare raw data with matches found for me in each of the DNA company's databases. I'm getting better and can now narrow down the ethnicity we share (based on what chromosomes we match on). This obviously helps with figuring out who our common ancestor might be, but I have much more to learn. When I have that a bit more figured out I will post here. 

Meantime if there are any readers who understand what I've posted today better than I do (or better than my explanation) please do leave a comment so we can all learn from each other's knowledge.  

7 comments:

CallieK said...

I don't think I can explain your results better than you have but I can offer a couple of book suggestions for reading about DNA. The first is The Juggler's Children by Carolyn Abraham which is a personal story about the author's search to find her family history with the help of DNA. The second is a more general overview of DNa itself, a very fascinating and well written book called The Violinist's Thumb:and other lost tales of love, war, and genius as written by our genetic code, by Sam Kean.

Astrid said...

Hi, nice post. One correction- mtDNA is not X chromosome. It is mitochondrial DNA, which has nothing to do with nuclear chromosomes like the autosomal, X, or Y ones tested by these companies. Mitochondria are organelles located outside the nucleus and have their own chromosome, so to speak, coding for 37 genes important to the function of mitochondria in the cell, which has to do with converting chemical energy into a form that can be used by cells. The mechanisms involved in sexual reproduction result in the survival only of the egg mitochondria and not of the sperm-- very simple explanation -- and therefore, this type of DNA is of maternal lineage only. Hope that helps.

Jana Last said...

Lorine,

I just received my Family Finder DNA results. This whole DNA for genealogy thing is just so interesting.

I want to let you know that your blog post is listed in today's Fab Finds post at http://janasgenealogyandfamilyhistory.blogspot.com/2013/10/follow-friday-fab-finds-for-october-11.html

Have a wonderful weekend!

Caverly said...

I am reading a new book called: The Juggler's Children: A Journey into Family, Legend and the Genes that Bind Us
Abraham, Carolyn
which is about a genealogy search using DNA and covers a little bit of the original history of commercial genealogy DNA.The book is were reading.

Mountain Mama said...

I would suggest "DNA and Social Networking: A Guide to Genealogy in the Twenty-First Century" by Debbie Kennett and Richard Hill's book "Finding Family with DNA Testing".

I tend to ignore the ethnic predictions since the companies seem to update them so often and focus on matching chromosome strings tied to Most Recent Common Ancestors (MRCA) or a surname from the same geographic area.

Consider uploading your autosomal raw data to GedMatch and FTDNA Family Finder, to locate wider number of distant cousin matches.

Good post and happy hunting.

Amanda Triepke said...

Ms. McGinnis,

I am the editor of the Marion County (FL) Genealogy Society Newsletter "Rootdigger". I would like reprint this blog post in our newsletter. Please let me know I can do this and how you would like it credited. Thank you.

Amanda Triepke

Lorine McGinnis Schulze said...

Hi Amanda - You may publish this post in your newsletter with the following credit between the lines -----

START credit here ----

by Lorine McGinnis Schulze
Olive Tree Genealogy
http://OliveTreeGenealogy.com

Previously published at http://olivetreegenealogy.blogspot.com/2013/10/understanding-your-dna-results.html

------END credit here

Please do be sure to include the credit above without changes