The Shared cM Project

For reference, here are all posts for the Shared cM Project:

Older Posts:

The portal for data submission is HERE.

Putting the Milkman Joke to Rest

[WARNING: I discuss or imply violent acts by ancestors in this post, read at your own risk].

We’ve all heard it. Some of us have even made it. A joke or implication about an affair or dalliance that conceived a child, often referring to the milkman or a neighbor. It’s usually directed to the biological mother, always ignoring or downplaying any act by the biological father, and is always consensual. The audience (whether in a Facebook forum or at a talk/seminar/webinar), seemingly always primed for the joke, laughs and the speaker moves on.

It’s time for this joke or implication, whether blatant or implied, to die the ignoble death it deserves.

An Admission 

A few years ago during a lecture, I make a flippant remark about a misattributed parentage conception. It may have been as simple as raising my eyebrows at a key moment, or even a simple pause that implied meaning, I don’t remember. After the talk, an audience member came up and called me out for being flippant about misattributed parentage conceptions. And the audience member was right, I had been flippant. I was wrong. ... Click to read more!

Examining Outliers in Shared cM Amounts – Part 2

In this blog post we will briefly review an extreme Grandparent/Grandchild relationship, where a grandchild appears to share just 9% of her DNA with a paternal grandmother rather than the expected 25%. All information is anonymized.

I’m a little afraid to post this article about an extreme outlier scenario. There is a danger that it could support misinterpretation rather than foster critical thinking. If you have a possible outlier scenario, be sure to try to disprove that it is an outlier situation, rather than simply proceeding as if is an outlier. Avoid confirmation bias!

This is the third post on my blog specifically examining outliers in confirmed relationships:

  1. Analyzing a Lack of Sharing in 2C1R Relationship
  2. Examining Outliers in Shared cM Amounts

Is it an Outlier? The Extreme Danger of Confirmation Bias

This was discussed in a previous article about outliers, but it bears repeating. ... Click to read more!

New Tools Everywhere! Exploring the New Tools at MyHeritage and AncestryDNA

The annual RootsTech convention at Salt Lake City in February has become a showcase for new tests and tools offered by the DNA testing companies. The biggest winner of all, of course, is the consumer!

Both AncestryDNA and MyHeritage announced major new developments at this year’s RootsTech. For example, AncestryDNA announced “MyTreeTags,” “New & Improved DNA Matches,” and “ThruLines,” three different tools currently in beta. The first two require an opt-in, while everyone is currently eligible for ThruLines. Meanwhile, MyHeritage announced “Theory of Family Relativity” and “AutoCluster,” both of which are currently available to members of their DNA database.

There is a LOT to digest with these tools, including knowing how to use them and understanding their limitations. To help you understand what the tools are and how to use them, I’ve created two new YouTube videos: ... Click to read more!

Examining Outliers in Shared cM Amounts

Sheryl, a member of the Genetic Genealogy Tips & Techniques group (which just broke 50,000 members!) recently commented on a thread about shared DNA outliers about a situation within her own family. I thought it would be a great opportunity to discuss outliers and how to deal with them. Sheryl kindly agreed!

For background, we examined an outlier situation once before on this blog, where second cousins once removed (2C1R) did not share DNA (see “Analyzing a Lack of Sharing in 2C1R Relationship“).

Identifying an Outlier

Sheryl indicated that she and her mother Grace appeared to be outliers with Sally, their first cousin (1C) and first cousin once removed (1C1R), respectively. Grace shared 482 cM with her 1C Sally, and Sheryl shared 215 cM with her 1C1R Sally. Not surprisingly, Grace and Sheryl share an expected amount for mother/daughter: ... Click to read more!

What? Can mtDNA Really Come From Dad?

It is canon that you received your mtDNA from your mother, who received it from her mother, who received it from her mother, back through time to Mitochondrial Eve. But could that canon be wrong?

Probably not. And even if some paternal mtDNA were to “leak” into and survive in the embryo, it would happen so rarely that it could only affect things like the timing to Mitochondrial Eve and population studies, NOT genealogical research.

[New] Research from PNAS

In new research from the journal PNAS published today (“Biparental Inheritance of Mitochondrial DNA in Humans“), which is unfortunately behind a paywall, researchers identified paternally-inherited mitochondrial DNA in 17 individuals spanning three unrelated families. What is missed from the media coverage, however, is that these families were identified because member(s) were presenting with conditions that made the researchers suspect a mitochondrial disorder. ... Click to read more!

Testing Artifacts to Obtain DNA Evidence for Genealogical Research

UPDATES:

  • December 2, 2018 Update from totheletterDNA (via their FB page) – there are 48 samples extracted and ready for genotyping. There are also 150 new samples undergoing extraction this coming week. All extracted samples will be genotyped before Christmas. Turnaround times should be improved moving forward due to having a “more streamlined process in place.”
  • November 18, 2018 Update – DNA was found in every sample analyzed, with the oldest being from 1930. All samples are being run through a second extraction method at the Garvan Institute of Medical Research, after which there will be quality checks of the extraction. Samples that went through two extraction methods will be genotyped twice, once for each method/sample.

Links to Other Blog Posts:

ORIGINAL ARTICLE:

Artifact testing promises to be an interesting component of the future DNA evidence and genealogy. If we can obtain and reliably identify DNA from deceased ancestors, relatives, or other individuals, we might be able to enrich our genealogical research.

For years I’ve been telling people that there is an enormous untapped market for artifact testing, and that they should hold on to their artifacts because a company will arise to offer this service. I typically follow that up by telling them NOT to literally “hold on to their artifacts” because I don’t want them to contaminate them! But seriously, there are many thousands, potentially millions, of artifacts that could possess DNA from long-dead individuals. ... Click to read more!

Using Semi-Anonymous Genetic Data in Genealogical Conclusions

The genealogical community has a serious issue we need to talk about.

We are amassing one of the largest collections of genealogical information ever created, in the form of DNA match data. As of October 2018, approximately 20 million people have taken autosomal DNA (atDNA) tests, and that number continues to grow rapidly. DNA evidence is being added as an additional record to support existing genealogical conclusion, being used to generate new hypotheses, and helping break down decades-old brick walls.

However, since many genetic matches are either unwilling or unable to respond to communication or provide permission for public use of the genetic data, much of the massive database is potentially locked behind privacy walls such that the information can’t be utilized in scholarship and can’t be publicly shared. Indeed, Standard #8 of the Genetic Genealogy Standards (PDF) mandates the following: ... Click to read more!

Introducing “DNA Match Labeling” – A Sorting Mechanism for AncestryDNA Matches!

Many DNA test takers have a wealth of genetic relatives! For example, I have more than 50,000 different genetic cousins across all the genealogy DNA testing companies. Although many regions of the world do not yet have 1,000’s of genetic cousins in their match lists, they will in the future as DNA testing grows increasingly popular and the testing companies target other countries.

Unfortunately, the testing companies have not provided users with the tools necessary to organize these matches. Indeed, clustering and organization of genetic cousins is a huge component of the future of DNA evidence. Clustering of our matches allows us to identify information that is not visible or apparent when the matches are unorganized.

This is where the DNA Match Labeling extension for Chrome comes in! I worked with a programmer to build this extension. ... Click to read more!

AncestryDNA Revises Ethnicity Estimates

AncestryDNA today (12 September 2018) released updated ethnicity estimates for all customers. Everyone in the AncestryDNA database will see some change in their estimate.

This update represents one of the most significant refinements of AncestryDNA’s ethnicity estimates. Both the reference populations and the ethnicity algorithm underwent significant development.

The size and makeup of the reference populations grew substantially, from ~3,000 reference samples to ~16,000 reference samples (many provided by test takers that consented to participating in AncestryDNA research). The update adds 17 new regions to the ethnicity analysis (from 363 to 380). Many more are needed in areas such as Asia and Africa, of course, but this is a great addition. As well, many regions were redefined or their names were changed to more accurately reflect the region. ... Click to read more!

DNA Central is Live!

DNA Central (www.DNA-Central.com), your one-stop resource for DNA education, has just gone live! See below for your special discount membership offer, a thanks for being a The Genetic Genealogist subscriber!

What is DNA Central?

There is an enormous need for DNA education. Millions of people are testing their DNA every year, but there are so few educational resources for those test takers. Receiving your results from the test company is just the first step in the process. How do you understand those test results? What do you do with them?

DNA Central is my effort to provide that DNA education in multiple formats. The membership-only website will provide resources for people at all levels trying to understand their results and stay on top of the most recent developments in DNA. These resources include: ... Click to read more!