Monday, September 28, 2015

How I DNA - Part One

The focus of my genealogy research lately has been on DNA matching. Working with DNA matches goes hand-in-hand with traditional DNA: you cannot locate the match connection unless you have a paper trail to use. I plan to write a few posts on what I do (and don't do) with my DNA and some mini case studies of real matches.

I started out with DNA testing in 2013 using 23andMe. At the time, they were the first of the "Big Three" companies to lower a test to $99. Good enough for me! Over the next year or so, I was able to test other family members, so I have multiple results to compare as well as having a view of how each of the tests work.

Here's what I did for testing:


I am not made out of money, so some of my decision making was financially-based, and some was obtaining as much information as I could. I'm fortunate that both of my parents are still living. They've put up with my genealogy stories for plenty long, so it didn't take much to convince them to take a test. All of these tests were autosomal (cousin-finder) tests that are applicable to both men and women. My last tester was my brother. In addition to the traditional autosomal test, he also took a Y-DNA test for me, so I had a test for my very unknown Irish male lineage in my DNA arsenal. 

Short of having everyone test everywhere, this lineup has been working pretty well for me. I have a wide variety of tests and results. With some family at multiple companies, it also helps to sort results between paternal and maternal families.

23andMe

This was my first company. It is a "spit" test. They provide ethnic breakdowns, Neanderthal percentage, haplogroups, general ethnicity by chromosome, and lists of matches by percent of DNA shared and by number of segments in common.

(+) Having my dad test there also allows MY matches to be designated "P" for paternal. What a plus! I don't take this to heart the farther away the matches become, simply because the shared DNA is too small. My dad has one grandparent who is French-Canadian, and easily 75% of his matches have ancestry from Quebec. If you have French-Canadian ancestors, test there!

(-) The biggest drawback is the connection system. You can opt for public or private. If you are private, your connections can see basics, but must agree to connect to see the actual DNA segments. The whole point, in my opinion, is having the segment data, so when a match does not reply or agree to share, it is very frustrating.

Here is a table of data for my dad at 23andMe, showing me in green and three of his first cousins. Who wouldn't want all that information?!


Family Tree DNA

Family Tree DNA (FTDNA) does autosomal tests and currently accepts transfers of DNA data from Ancestry. This is how my mom and I moved our data to FTDNA. My brother took their "cheek scraper" autosomal test. FTDNA provides ethnic breakdowns, match lists, longest segment shared, ability to add a family tree, an ICW (in common with) list, and several other features. It's a little clunky, but provides great information.

(+) Using the ICW list is helpful in determining who a match might also match. Using the list, as well as any tree information, you may be able to narrow the connection. ICW does NOT mean they all match each other in the same place, but in a more broad sense; think Six Degrees of Kevin Bacon. FTDNA also has a chromosome segment map that is very useful.

(-) Two of the bigger drawbacks using FTDNA are that (1) they tend to overestimate the closeness of a match, and (2) your matches are sorted by largest block of DNA, not total amount. When you dig a little deeper with your matches, sometimes you'd rather have total DNA shared, not just the longest block.

Here's what my top four DNA matches look like on FTDNA. First is my mom, then my brother, then a maternal match and then a paternal match:


Ancestry

Ancestry has so many features going on - good and bad - that I will leave them for their own post!

Thanks for reading!

© 2015 Sally Knudsen


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