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Better matching, a chromosome browser

The standard advice when it comes to DNA testing has long been the same.

Test everybody you can, getting the results into as many databases as you can.

The simple reason is that DNA testing — and particularly autosomal DNA testing (the kind done at AncestryDNA, at 23andMe and in the Family Finder test at Family Tree DNA, for example) is the functional equivalent of fishing for cousins who may have family photos, the old family Bible, the family information we need — and using our DNA as bait.1

The problem is … every one of those testing companies is like a different pond to fish in. And we have no way of knowing, until we get that hit, just which pond that critical cousin match is in.

So… we test everybody we can, getting the results into as many databases as we can.

Which, of course, ain’t cheap.

So we prioritize: we test first where the pay-off is likely to be greatest and then add other ponds as we can afford to.

Until now, one pond The Legal Genealogist hasn’t put high on the priority list has been MyHeritageDNA, one of the newest kids on the autosomal testing block. Although it has a lot of long-term promise, particularly because of its international scope and its reach into Europe where so many of our ancestors came from, it also had some issues — the big one being with its matching system. Too many people were being matched to folks who didn’t match their own parents (and you can’t have any autosomal DNA that your parents didn’t have).

But MyHeritage did two things this past week that put it right into the mix with other genealogical DNA testing companies. It greatly improved its matching system — and it added a chromosome browser.

The matching system issue had been widely reported.2 I couldn’t test it myself, since neither of my parents was alive when autosomal testing first became available, but a cousin who compared her own results to her parents found that as many as four of 10 of her matches didn’t match either of her parents. Those were either false positives to her (people who shouldn’t match her and did) or false negatives to one of her parents (people who should match one of them and didn’t).

But in a major upgrade this past week, MyHeritage has addressed the worst of the matching system problems. The announcement from MyHeritage on Thursday promised “more accurate DNA Matches; more plentiful matches (about 10x more); fewer false positives; more specific and more accurate relationship estimates; and indications on lower confidence DNA Matches to help focus research efforts.”3

And folks like my cousin who have parents who’ve tested confirm that the system upgrade is addressing the worst of the matching problems. In my cousin’s case, the mismatch percentage dropped from 40% to around 18% overall — and the new system lets you shunt off low confidence matches that are at a higher risk of being false positives so you can concentrate your research efforts on the high-confidence results. MyHeritage promises that the new system is “so good, that the percentage of child-only matches that are not flagged as low or medium confidence, is now less than 5%.”4

The upgrade to the matching is a big step forward, and one that lets me move MyHeritage, cautiously, into the recommended column.

Pushing that along is the addition in this upgrade of another tool that’s very useful for research: a chromosome browser. This is a tool that lets you see exactly where in your DNA you match each person the testing company says you match.

And here I can test it, because I have my results in enough places that have chromosome browsers and many of my matches do as well. So I can see my chromosome browser results against, say, that fellow-genealogist-cousin of mine at, say, both MyHeritage and Family Tree DNA.

Chromosome browser compare

As you can see, the match-up is pretty close. It won’t be exactly the same, since the sampling between the two companies isn’t exactly the same, but there are no reasonably-sized segments being reported at one and not at the other.

It’s a big step forward for MyHeritage and, with its potential for getting more international testers into the DNA pool, a very welcome step forward.


SOURCES

  1. See generally Judy G. Russell, “Baiting the hook,” The Legal Genealogist, posted 16 Feb 2014(http://www.legalgenealogist.com/blog : accessed 13 Jan 2018).
  2. See e.g. Leah Larkin, “MyHeritage Matching,” The DNA Geek, posted 21 July 2017 (http://thednageek.com/ : accessed 13 Jan 2018).
  3. Yael, “Major Updates and Improvements to MyHeritage DNA Matching,” MyHeritage Blog, posted 11 Jan 2018 (https://blog.myheritage.com/ : accessed 13 Jan 2018).
  4. Ibid.
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