Join Lisa at GeneaQuest 2018 in Illinois

Lisa Louise Cooke will be at CAGGNI’s GeneaQuest 2018 in Hoffman Estates, Illinois on Saturday, June 23. Join her and other expert presenters all day to learn Google strategies for genealogy, a master plan for organizing your research, DNA solutions, brick-wall...

Thumbs-Up: AncestryDNA Improves Genetic Matching Technology

ancestrydna matches improvedDouble good news: AncestryDNA has made some improvements to the way they calculate your genetic matches, but they haven’t messed with the site format or layout. There is one downside–so keep reading.

Change is afoot at AncestryDNA. Again.

While stability and predictability seem like honorable qualities in a company or product, when it comes to tech tools, in the ears of tech companies, those words sound more like dated and old. Of course, we are used to this by now. I had a client tell me recently that he wanted to be in touch sooner, but his grandson “upgraded” his computer to Windows 10 and then promptly left for college the next day, leaving him fighting with a new interface and operating system.

The good news is, you won’t have this problem with Ancestry’s new update. There aren’t any changes to the interface or the layout of the information. In fact, many of you will not even notice at first that your match list has changed. You’ll just see this notification when you log in:

AncestryDNA match improvement announcement

But in fact, there likely have been some adjustments made to your match results:

  • Some of your third cousins have been demoted to fourth cousins.
  • Some of your fourth cousins have been demoted to 5th-8th cousins.
  • Some of your Distant Cousins have disappeared off your match list
  • You have new cousins on your Distant Cousin match list.

In general, from what Ancestry has showed us, you gain more than you lose.

Changes in the dregs of your match list may not seem like that big of a deal. But Ancestry has made some big changes in the way that they are calculating matches. They are getting better at it. Which means you match list is now more representative of your ancestral connections, even at the very distant level.

There are two big pieces to this matching puzzle that Ancestry has tinkered with in this latest update: phasing and matching.

You will remember our discussion on DNA phasing and how it can impact your matching. Ancestry has developed a robust reference database of phased DNA in order to better phase our samples. Basically, they have looked through their database at parent-child duos and trios and noted that certain strings of DNA values often travel together. It’s like they have noticed that our DNA says “A black cat scared the mouse” instead of  “The brown cat ate the mouse” and they can then recognize that phrase in our DNA, which in turn helps our DNA tell the true story of our heritage.

In addition to updating the phasing, Ancestry has revamped their matching method. In the past they viewed our DNA in small windows of information, and then stitched those windows together to try to get a better picture of what our DNA looked like. Now instead they have turned to a point-by-point analysis of our DNA. Again to use a sentence example, with the window analysis we may have the following sentence windows:

ack and J

ill went t

he hill t

etch a pai

l of water.

AncestryDNA match comparisonOf those windows, you may share the “etch a pai” with another individual in the database, earning that cousin a spot on your match page. However, the truth is, that bit could say “sketch a painting” or “stretch a painful leg” or “fetch a pail.” With Ancestry’s new method, they are able to see farther on either side of the matching segment, making this clearly “fetch a pail.” That means better matching, which means more confidence in your cousin matches.

The downside to this update is going to come in the reorganization of some of your relationships. Ancestry has tightened their genetic definition of your third and fourth cousins. Basically, that means that some of your true 3rd cousins are going to show up as 4th cousins, and some of your true 4th cousins are going to be shifted down into the abyss of 5th-8th cousins.

This brings us to the downside of this AncestryDNA update: changes to the Shared Matches tool. The shared matches tool allows you to gather matches in the database that are related to you and one other person, provided you are all related at the 4th cousin level or higher. This tightening of the belt on 4th cousins means that some of them are going to drop through the cracks of that tool, really limiting its ability. Grr. Hopefully, Ancestry will fix that, and expand this tool to include all of your matches. They have their fairly good reasons for this, but still….

So, as the winds of change blow yet another iteration of the AncestryDNA match page, I think we can see this as an overall win for doing genealogy with our genetics at Ancestry.

More AncestryDNA Gems


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AncestryDNA Results Improving for Jewish and Hispanic Ancestry

dna_magnifying_glass_300_wht_8959Ancestry.com has improved the ability of AncestryDNA to find good matches for Jewish, Hispanic and other ancestries that maybe weren’t so precise before. Here’s the lowdown, quoted liberally from Ancestry.com’s press release:

The problem: Predicting genetic relatives among customers of Jewish and Hispanic descent and some other groups. “In DNA matching, we are looking for pieces of DNA that appear identical between individuals,” says the release. “For genealogy research we’re interested in DNA that’s identical because we’re both descended from a recent common ancestor. We call this identical by descent (IBD). This is what helps us to make new discoveries in finding new relatives, new ancestors, and collaborating on our research.”

“However, we also find pieces of DNA that are identical for another reason. At one extreme we find pieces of DNA that are identical because it is essential for human survival. At the other, we find pieces of DNA that are identical because two people are of the same ethnicity. We call these segments identical by state (IBS) because the piece of DNA is identical for a reason other than a recent common ancestor. This, we have found, often happens in individuals of Jewish descent.”

“The challenge in DNA matching is to tease apart which segments are IBD, and which ones are IBS….Most Jewish customers find that we predict them to be related to nearly every other Jewish customer in the database….Detecting which cousin matches were real and which ones were bogus has always been a challenge for these populations.”

First step toward a solution: “By studying patterns of matches across our more than half a million AncestryDNA customers, we found that in certain places of the genome, thousands of people were being estimated to share DNA with one another–likely a hallmark of a common ethnicity. Our scientific advancements… have allowed us to effectively “pan for gold” in our matches–by throwing out matches that appear to only be IBS, and keeping those that are IBD.”

“While the problem was more pronounced in customers of Jewish and some Hispanic descents, we observed this problem across all ethnic groups.  So, all customers will see increased accuracy of their DNA matches, and significantly fewer ‘false’ matches.”

AncestryDNA results with better matches found by this method “will be available in the coming months,” says the release. They plan to email existing customers when results are ready.

How to Watch Elevenses with Lisa

How to Watch Elevenses with Lisa Elevenses with Lisa is a free weekly genealogy webinar show by Lisa Louise Cooke. It premieres live and then is available to watch as a video replay both here on our website and the Genealogy Gems YouTube channel. Over time older...

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