Review of the DNA Study Group: Playing With Matches

The following post is from Red Rider, host of the SL DNA Study Group. You can join us for these meetings at 5:30 p.m. SLT (same as Pacific Time), on the 1st and 3rd Sundays of each month at the Family History Centre in Second Life.

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Our last SL Family History Centre DNA discussion focused on working with matches. After initially going through our matches when we get our results it’s necessary to return to our results pages frequently in order to keep up with the continual flow of matches.

I generally review new matches at least once a week. Both 23andMe and AncestryDNA have filters which will list your most recent matches from newest to oldest. You need to click on the drop down menu at 23andMe, then click newest matches. At AncestryDNA there is a new match filter button in the top left portion of the match list page. At Family Tree DNA it’s easiest to just click the date at the top of the match list. This will display newest matches at the beginning of the list. At GEDmatch new matches’ kit numbers are highlighted in green.

After shifting my newest matches to the top of the list I will then take a look at the best matches, those that share the most DNA. I will click on those at AncestryDNA and 23andMe. I will then check for common surnames if a tree, or name list, is available. At Family Tree DNA you need to click the pedigree chart icon, below the match name, to see a full tree. Sometimes surnames are listed on Family Tree DNA’s match list pages. At AncestryDNA and Family Tree DNA I will then click shared matches or common matches. This can help narrow the possible relationship if they match someone I’ve already established a relationship with. At 23andMe you will need to compare matches with each other in the chromosome browser, in order to see if they are related to one another.

At Family Tree DNA it’s a good idea to compare your common matches in the chromosome browser to see if you can find triangulations.

I also check for matches who share my surnames by searching my match lists. All of the companies allow you to do this. The companies also provide the ability to create notes for matches. At AncestryDNA you can star interesting matches.

At AncestryDNA I often take a look at hints which will be displayed if you click the hint filter located near the new filter, at the top portion of the match list. You can also access hints from the AncestryDNA home page. You will receive hints for matches who have the same ancestral couple, or ancestor, on their tree. AncestryDNA will than display exactly how you and your match are related. The hints need to be taken with a grain of salt because it’s possible you may share other ancestors besides those on your trees.

Someone at the last discussion reminded me that you can sometimes preview trees at AncestryDNA even if the match list says a match doesn’t have a tree. This is possible because some matches have Ancestry trees but have not attached them to their DNA results.

tree match

I also just noticed that you can download all of your matches’ ancestors’ names. There is a button you can click at the bottom of the name list on your matches’ page. A CSV document will then be download to your computer with all of their names. This may be quicker to review if a match has a large tree.

Our next discussion on April 3rd, at 5:30 SLT (or Pacific time), will explain how segments are used to establish relationships with matches. I’ll also talk about how mapping segments helped me discover a wrong connection I had made with a match.

Notes From the Second DNA Study Group Meeting

The following post is from Red Rider, host of the SL DNA Study Group. You can join us for these meetings at 5:30 p.m. SLT (same as Pacific Time), on the 1st and 3rd Sundays of each month at the Family History Centre in Second Life.

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At the second meeting of our SL DNA discussion group, I went over some DNA jargon. If you want to get the most out of your DNA results, it is important to read about the subject. Joining groups at Facebook such as the ISOGG group, or the DNA Newbie group, is also a great way to learn about the subject.

Reading about new findings in the field, and joining groups, helps us stay on top of changes regarding the evaluation of our results. Genetic genealogy is a new field, and the interpretation of our results is subject to change. Since DNA terms are not always explained, it is helpful to look at some of these terms and definitions before embarking on further study of the subject.

Here are my slides with the terms and definitions we went over on Sunday, March 6:

 

A new blog post by Roberta Estes, “Concepts – Identical by…Descent, State, Population and Chance,” introduced me to some new terms for defining Autosomal DNA (atDNA) segments. Identical by chance or coincidence, or “IBC,” for one.  This would apply to matching segments not shared by parents, or not inherited through your parents. Identical by population, or “IBP,” would be segments which are common to particular populations, such as ethnic populations. These segments are not considered “identical by descent” because they cannot be attributed to a common ancestor. However, in the case of population segments, “IBP,” they can sometimes be useful if you can link the segment to an ancestor because they are the only possible source of the population segment.

IBP segments lead me to a term I left out Sunday. I forgot to include “pile ups.” This term is used to  refer to these population segments.  A pile up is literally many people sharing a segment in the same location (see illustration below). AncestryDNA removes populations segments using their Timber filter. The other companies do not.

dna

When it comes to the interpretation of results, Autosomal DNA is the most challenging to work with, which is why I included so many terms for this test in my “DNA Jargon” presentation. For instance, we need to know something about the statistics regarding whether a segment is IBD or not. We need to build out our trees as far as we can in order to draw accurate conclusions from our shared segments. We need to collect and map segments. We need to compare trees carefully looking for all possible shared ancestral lines, especially if we are from endogamous populations. These complexities have resulted in the proliferation of terms and acronyms.

Finally, I suggested we might discuss topics being discussed at the Facebook ISOGG group during our SL Sunday chats. Anyone can ask to join this Facebook group. An ongoing topic is how we determine whether autosomal DNA segments are IBD. I suggested reading “Another Triangulation Success, Another Etne Cousin” by Kitty Cooper, as well as the comments below the post at Facebook.

Since not everyone attending the Sunday discussions has tested yet, we will go through the testing process in more depth, and talk about what we can do to get the most out of our results, at the next meeting. See you there! 😀

Questions? Contact Red Rider for more information.

DNA Study Group: 1st Meeting Re-Cap

 

The following is a guest post from Red Rider, who serves as moderator and host of our DNA Study Group.

The first meeting of our DNA Study Group at the Second Life Family History Centre was an overview of all types of DNA tests available. Autosomal (atDNA), Y DNA, and mitochondrial (mtDNA), are the 3 tests offered by the genetic testing companies. Only Family Tree DNA offers a list of genetic matches with their Y and mtDNA tests.

Here is a review of some of the material we covered:

  • Y DNA is only passed down to sons from their fathers. It only traces the direct male line. This is a marker test. The cost of the test depends on the number of markers tested; 12 to 111 marker tests are available. Mutations on markers change the numerical value assigned to marker testers. The marker mutations separate family lines. Y DNA tends to mutate frequently enough for it to be useful in separating family lines.
  • Mitochondrial DNA, or mtDNA, is passed down from mothers to sons and daughters. Fathers do not pass their mtDNA down to their children. This test is good for solving problems along the direct maternal line. The partial mtDNA test, which generally includes HVR1 and HVR2, can include cousin matches who share ancestors over 28 generations. Or around 700 years ago. The full sequence test helps eliminate matches beyond the genealogically relevant time period. Full sequence matches generally share an ancestor within the past 500 years. The reason these matches can share ancestors so far back in time, and still match us, is mtDNA mutates slowly. As with the Y DNA mutations are used to assign matches. Mitochondrial DNA mutates more slowly than Y DNA.
  • The autosomal test is the most popular because it provides more comprehensive results. Instead of just looking at the male or female lines this test includes all inherited DNA lines. We inherit half our autosomal DNA from each parent. Roughly a quarter of our atDNA comes from each grandparent. Recombination means that we share varying amounts of DNA from more distant ancestors. This test is offered by the 3 major testing companies, i.e., 23andMe, AncestryDNA, and Family Tree DNA. Matches are assigned based on matching segments on our autosomal chromosomes. This test is most accurate for close relatives. More distant relationships require verification using traditional genealogy research methods.

Future meetings will focus on the vocabulary used in genetic genealogy, and resolving problems encountered when using DNA to solve genealogy problems. Group member discussions will allow us to share our experiences with using DNA for genealogy. There have been heated debates on genealogy forums, and in the media, about exactly what DNA purports to tell us, and what can really been proven using DNA. We’ll discuss some of these challenging issues during our next Sunday discussions.