Archives

Eliminating the DNA Matches from One Side

Aug16

UPDATE 26-Oct-2018: Click here for this tool  –  Extract Desired Lines

Unless you get lucky with a first cousin or closer match, searching for an unknown parent or grandparent involves building lots of trees for your DNA relatives and looking for common ancestors among them. Then you build down from those ancestors looking for someone in the right place at the right time. It is best to have two pairs of common ancestors because then you are looking for where their descendants meet in a marriage.

Sample ancestor list from GWorks – linked to slide in my GWorks presentation – using-dna-for-adoption-searches

It is wonderful to have automation to compare trees for you. The GWorks tool suite from DNAgedcom.com does just that and, no surprise, I have written many blog posts about how to use those tools. They can collect all your Ancestry matches and then all the ancestors in their DNA connected trees and give you a list of the most frequently seen ancestors. You can also upload GEDcoms collected elsewhere or created by your own research to use in the comparison.

There are many times I would like to automatically exclude half the ancestors collected from Ancestry. For example when I am helping a person who knows only one parent but has a half sibling or the known parent tested. Specifically when they look at the results from a GWorks run, how do they eliminate the matches from the other side?

View Trees with an example for deleting

One way is to go to the “View Trees” on the GWorks menu at DNAgedcom and delete all the trees from the known side by clicking the red X to the far right of each tree. Then rerun the “Match GEDcom files” in the Manage Tree Files function. This could take forever in a half sibling case.

However, it is very useful to delete trees when one person has tested multiple family members and they are all in the same tree. In that case I keep the tree for the person who is further up the line. Very conveniently you can click on the tree name to go to that match at Ancestry, as long as you are logged in there, so you can easily figure out which one to keep. But again, this is too lengthy a process for a half sibling case.

DNAgedcom client home window

I have long used the Match-O-Matic (M-O-M) feature in the DNAgedcom client (DGC) to get the lists of matches for just one side (the m_ file) in a spreadsheet for use to keep track of my research. However M-O-M does not work for the tree files (aka the a_ file – actually it has a list of ancestors and which trees they are from).

Sometimes it is good to be a programmer. I have put together a new tool that you can use with a list of matches, for example the match file from M-O-M, to create a new tree file with only those trees that are for the matches in the match file. Then you can upload that match file and the new tree file to DNAgedcom for use in GWorks.

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New Compact Chromosome Browser on GEDmatch’s GENESIS

Aug10

Today GEDmatch launched a version of my segment mapper which is integrated with their database. It can be used as a way to easily visualize multiple matches on GENESIS. This first version shows how everyone compares to the first person on the list, like the current 2D chromosome browser but more compact. Also each color is a person.

My Munson cousins in my new compact segment mapper at Genesis

Above is the screenshot of my Munson cousins which even shows one of the boxes that appears when the cursor is placed on a segment. Click on this image to see a copy of the html version (edited for privacy) where you can put your cursor on any segment to see the details. (N.B. when you put your cursor on a segment and the information pops up via javascript that is called a mouse over in geek speak. )

One way to get a display like this at Genesis is to check the boxes (tier 1 only) next to your best matches in the one-to-many (up to 40 of them) and then click the button “Visualization” at the top of the page. Another way to get there is to use the Tier 1 tool “MultiKit Analysis” and select the kits you want to look at. Remember the first kit listed is the one that all the others will be compared to.

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When the DNA says your parents are related

Jul25

One of the first things I do when helping someone with their DNA results is to check if their parents are related. This can explain unusual patterns of matches, for example, all seemingly from one side.

GEDmatch.com has a nice tool called “Are Your Parents Related” (AYPR) in the”Analyze Your Data” blue panel (middle right of page) which looks for places in the specified kit where the DNA is identical on both chromosome pairs, maternal and paternal. This happens when you inherit the same segment of DNA from each parent because they are related. We call this a homozygous run which is a fancy way of saying a stretch of identical DNA on both sides.

CeCe Moore specializes in helping people who make this discovery. Click here for the informational brochure she helped Brianne Kirkpatrick, genetic counselor, create. It includes where to get emotional support.

My goal is to help you figure out what the DNA means yourself. Can you deduce what the relationship of those parents is? Well a very simple rule of thumb is to multiply the shared DNA from AYPR tool by four and look up that new total at the DNA painter calculator for the possibilities. Then do further family DNA testing to confirm.

Why does this work? Let’s look at the numbers. Suppose your parents share 25% of their DNA. They will pass about half of that to you, so 12.5%. However only about half of that will be the same DNA so it will show up as about 6.25% on the AYPR tool.

Look at the image. The total is 215.3 when you multiply by 4 you get 861.2. You might look that up before you read on …

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An Online DNA Conference from FHF

Jul5

The thing I have disliked in the past about doing webinars is the lack of audience feedback. I really enjoy explaining my passion to a group of people, seeing their reactions, and then answering their questions. That is so much better for me than talking into a microphone while going through my slides.

Practice FHF online presentation, Sam, Andy Noel of FHF, and myself (0nly one person shows when presenting)

The software that Family History Fanatics (FHF) uses for online conferencing lets me see the chat comments and shows my face in the corner while I present my slides. Plus I can switch to full face mode, which I plan to do when answering questions. I think this will be a much better way for me to do a webinar, so I welcome you all to register for the FHF one day DNA conference – A summer of DNA on Saturday, August 4. I will be joined by Diahan Southard, Sam Williams, and Michelle Leonard. After all the talks there will be a panel including a Q+A. Continue reading →

An Endogamous Success Story

Jun29

It is difficult to solve adoption cases in endogamous communities because everyone will share the same 4th and 5th grandparents, often multiple times, so the methodology for finding a birth parent from 3rd and 4th cousin matches just does not work. You have to wait for a few second cousin or closer matches.

Tessa was looking for her unknown biological father. Her mother had given her a name, Rudy Padilla, and said he was perhaps Mexican. I ran a GWorks for her which I showed in my lecture about unknown parentage at the SCGS Jamboree. This is the full story.

The Compare Trees at DNAgedcom from GWorks for Tessa

I had never seen ancestors who were in 30-40 trees before! How can that be? Perhaps endogamy? Then I looked at the names and recognized many of the surnames. These are the Spanish soldiers who were among the earliest European settlers of New Mexico.

New Mexico in 1824 from Wikipedia, click image for the article (see *map credits)

These soldiers who came to the Southwest in the 1600s and 1700s mostly had to take Pueblo women as brides or not get married. A few brought wives with them from Mexico of presumed Spanish descent. For many years these Spanish “first families” of New Mexico hid the native part of their roots. Now many are proud of this heritage. Click here for an article about that which mentions the New Mexican woman in those Ancestry ads who discovered her Native American roots with DNA. By the way, Tessa shows 17% Native American at Ancestry.

I told Tessa that success finding her dad could take a very long time since she would need to wait for close matches, but to please upload to MyHeritage and Family Tree DNA to look for more relatives. She had tested at both 23andMe and Ancestry DNA.
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