Last week I published “Small Matching Segments – Friend or Foe?” to join in the community’s conversation about the use of “small” segments of DNA, referring to segments 5 cM and smaller (although keep in mind that the term “small,” without a more specific definition, will mean different things to different people).
The question that the community has been struggling with is whether small segments of DNA can be used as genealogical evidence, and if so, how they can be used.
As I wrote in my post, a significant percentage of small segments are false positives, with the number at least 33% and likely much higher. In my examination and in the Durand paper I discuss, a false positive is defined as a small segment that is not shared between a child and at least one of the parents.
There has been a great deal of conversation in the genetic genealogy community over the past couple of weeks about the use of “small” segments of matching DNA. Typically, the term “small” refers to segments of 5 cM and smaller, although some people include segments of 7 cM or even 10 cM and smaller in the definition.
The question, essentially, is whether small segments of DNA can be used as genealogical evidence, and if so, how they can be used.
While it may seem at first that all shared segments of DNA could constitute genealogical evidence, unfortunately some small segments are IBS, creating “false positive” matches for reasons other than recent ancestry. These segments sometimes match because of lack of phasing, phasing errors, or a variety of other reasons. One thing, however, is clear: there is no debate in the genetic genealogy community that many small segments are false positive matches. There IS debate, however, regarding the rate of false positive matches, and what that means for the use of small segments as genealogical evidence.
Short Summary: Before the end of the year, AncestryDNA plans to update our match lists using a new algorithm that reduces the number of false positive matches. For the first time, matching DNA segments will be characterized as IBS (i.e., a false positive) based on something other than simply segment length.
Last Monday, October 6th, I and six other members of the genetic genealogy community attended a ‘Bloggers Day’ hosted by AncestryDNA at the San Francisco headquarters of Ancestry.com. Two other members of the group have already written about the event:
While at ‘Bloggers Day’ we discussed many issues including the Y-DNA and mtDNA databases originally scheduled for destruction, upcoming changes to AncestryDNA’s matching algorithm (much more below), and other upcoming changes to the AncestryDNA about which you will hopefully soon hear much more.
What It Does: This Excel based tool sorts and groups your chromosome browser results from FTDNA into overlapping DNA sets and assigns the ICW status within the set. By following the paper “Combining Results from All Tests” , the tool can also be used to organize the output from all three testing services. You must have Excel to use this. A Mac Version is also available.
Directions: Full directions are found on a link with in the product interface on dnagedcom.com
For the next week or so, 23andMe is pausing updates to the DNA Relatives feature. This feature provides a list of genetic matches and estimates the range of relationship.
According to this week’s 23andMe update entitled “Release Notes: 7 June 2013,” (you must log in to view), “The computation time for DNA Relatives and Ancestry Composition has been growing.”
Going into greater detail at “DNA Relatives computations temporarily on hold,” 23andMe explains that due to the increased computational time, and in an effort to reduce the time it takes to generate DNA Relatives matches, updates are paused. Accordingly, “[t]his means that you won’t be receiving new matches to your existing DNA Relatives list, and if you haven’t received your matches yet there may be some additional waiting time.”
For a limited time, Family Tree DNA is offering Family Finder Transfers for $49, reduced from the normal cost of $99.
The Family Finder Transfer program gives those who have taken an autosomal DNA test with Ancestry.com or 23andMe the ability to import their autosomal DNA results to Family Tree DNA.
According to the website, purchasers of the Family Finder Transfer program receive:
A myFTDNA 2.0 account (personal page), if a new customer;
Autosomal DNA results uploaded to and stored on Family Tree DNA’s servers;
Matching to all autosomal Family Finder results in our matching database;
Ethnic origins results from our Population Finder program; and
All standard tools and pages associated with the autosomal Family Finder test and the Population Finder program.
The uploaded files are batched once a week then run through the conversion program, and results typically take between 6-10 weeks based on volume. Customers are notified by e-mail when their results are available.
Why Transfer Your Results to FTDNA?
If you’ve already tested at Ancestry.com or 23andMe, you might wonder if there are any benefits to transferring your results to Family Tree DNA.
As I noted in a recent blog post (see “WDYTYA Reveals More Information About Ancestry.com’s New Autosomal DNA Testing“), autosomal DNA testing was featured in the recent episode of Who Do You Think You Are with actor Blair Underwood. After revealing Mr. Underwood’s biogeographical estimates (74% African American and 26% European), they revealed a genetic cousin found in the Ancestry.com’s database:
The service identified a distant cousin (somewhere around the 10th cousin range) who lived in Cameroon (an Eric Sonjowoh). Mr. Sonjowoh was already in the Ancestry.com database, which is why they were able to compare him to Mr. Underwood. According to Eric, someone approached him in 2005 and asked him for his DNA because African Americans were trying to trace their family back to Cameroon. I’m not sure what database the DNA was in, but it shows that Ancestry.com has pre-populated its database with at least some samples from other public and/or proprietary data sources.
[Update (2/24/12): Some genealogy forums are reporting that callers to Ancestry.com are being told that the autosomal DNA test will publicly launch in approximately 1 month (late March or early April).]
Tonight’s episode of Who Do You Think You Are? featured African-American actor Blair Underwood. For those not familiar with Who Do You Think You Are, the 1-hour program examines the genealogy of a celebrity, typically focusing on one or two of their most interesting families.
This episode was of particular interest to me because it featured Ancestry.com’s new autosomal DNA testing service, which I’ve written about before (see “Ancestry.com’s Autosomal DNA Product – An Update”). While there wasn’t too much new information about the DNA product in this episode, it was an interesting sneak peek at the service.
As I’ve stated many, many times in the past, the future of genetic genealogy is combining test results with both family trees and paper records.
Today, MyHeritage and Family Tree DNA announced a partnership that will bring that future one step closer to reality. MyHeritage will offer a full line of tests (13 in total) through FTDNA, including these basic introductory tests (with discounts – not shown below – for MyHeritage subscribers):
Y-DNA12 (12 Y-STR markers) – $99
mtDNA (HVR1 region) – $99
Family Finder (autosomal test) – $298
The FAQ page for the tests is here (and I note that although they currently do not allow import of test results from other providers, they plan to in the future). I wonder if existing FTDNA test-takers can import their results?
Given MyHeritage’s worldwide reach and enormous membership (62 million members around the world!), it will be interesting to see whether this new partnership expands genetic genealogy testing in other parts of the world, which have been slow to try this technology.
As you may have heard, I recently made my 23andMe and Family Tree DNA autosomal testing results available for download online at “mygenotype,” and dedicated the information to the public domain (if dedicating DNA sequence to the public domain is even possible – I’m currently doing some research in this area and expect to write more in the future).