Wednesday, June 27, 2012

Multiple cousin relationships and shared DNA: Endogamy and Consanguinity

I have read a number of posts about endogamy and shared DNA in regard
to the Ashkenazi "Jewish correction" used by 23andme and how it keeps
Ashkenazi Jews from seeing their non-Jewish cousins. Because of the
many intermarriages among European Jews the genetic relationship
predicted is often greater than that expected from the documented
genealogical relationship. These predicted higher or closer relations
push out the genetically smaller but documented higher genealogy

Many of the Ashkenazi cannot determine the relationships being shown
since the predicted range is too close and their pedigrees are not
detailed enough to make the connection. Below I'll give a non-Jewish
endogamy example where the relationships can be determined.

Last night I received a predicted 2nd cousin at 23andme.  The per cent
of shared DNA is 3.02 in 13 segments for 226cM. He (call him A) is
actually one of my multiple cousins. We (I am B) are 3rd cousins, 3rd
cousins once removed, half 3rd cousins once removed, 4th cousins, 5th
cousins, and triple 6th cousins.

Compared to my multiple 1st cousin (C) they share 10 segments for 151cM.

Compared to my and my 1st cousin's maternal double 3rd cousin once
removed (D) they share 1 segment of 0.9cM.

A is related to B and C on both maternal and paternal lines and to D
through his paternal grandmother.
B is related to A and C on both maternal and paternal lines and to D
on 2 maternal lines.
C is related to A and B on both maternal and paternal lines and to D
on 2 maternal lines.
D is related to A on one maternal line and to B and C on 2 maternal lines.

In all of these cases the predicted relationship, based on DNA shared,
was one generation closer than the documented relationship mainly due
to the high degree of endogamy and the resulting consanguinity.

Now I am waiting for A's wife's results, she is my 3rd cousin once
removed and, yes, we share multiple lines of ancestry. ;^)

Wednesday, June 13, 2012

Genetic Genealogy course from the National Genealogical Society


What’s Happening at the 

National Genealogical Society, 13 June 2012:

New NGS Course: Genetic Genealogy, The Basics
NGS proudly announces the release of its newest American Genealogy Studies course, Genetic Genealogy: The Basics. The course was developed by Dr. Thomas H. Shawker who is a physician with the National Institutes of Health, a nationally recognized lecturer on genetics, and chairman of the NGS Genetic Genealogy Committee.

Dr. Shawker shares his medical expertise in this six-lesson self-paced course. Topics covered in the course include
·    the structure of the DNA molecule, how it is organized, how it replicates, and how it functions;
·         human chromosomes and how the Y chromosome is inherited;
·         the two types of DNA markers used in genetic genealogy;
·         haplotypes and haplogroups;
·    evaluation of a Y chromosome surname project and a discussion on how to evaluate the test results of the participants; and
·    the structure of the mitochondrial DNA molecule, how it is inherited, and how it can be used in genealogy. 

Genetic Genealogy, The Basics is designed for independent study. Students check their work with an answer key that immediately follows each self-test. The course is available on a PC- or MAC-compatible CD in a PDF format. The tuition is $45.00 for members and $70.00 for non-members.

Please visit the course web page at for more information and to register for the course.

Sunday, June 10, 2012

Two discount codes for the FTDNA Family Finder test

The codes below will get a Family Finder autosomal DNA test at Family Tree DNA for $179 each.  That is a $110 discount from the regular price.  The Family Finder test can help you identify genetic cousins within the past five generations and beyond.

The codes must be used today, 10 June 2012 at

Your coupon code is FF5CAD9E2684, we appreciate your past participation and invite you to share it with a friend or family member. 

Your coupon code is FF5C4470B2298, we appreciate your past participation and invite you to share it with a friend or family member. 

  Special Note: Coupon code has a firm expiration date of June 10th 2012 and is good for one use only. Offer only valid for credit card payments. Enter the coupon code during the checkout process to purchase at the promotional price.

FTDNA does not test known medical DNA locations.

Friday, June 08, 2012

Have you tested Family Finder at Family Tree DNA? Check your email!

FTDNA has provided a discount certificate to everyone who has already had the Family Finder test at FTDNA. Check your FTDNA email now to see if you have a certificate. You MUST USE it by the 10th of June to get the Family Finder test at a discount of $110 from the regular $289 price. You should have as many certificates as tests you have paid for.

Remember that this is an autosomal DNA test and can be used by both males and females to find your relatives from the past 5 generations.

This is a great opportunity to test more family members.

New Ancestry features at 23andme

Today, at the Southern California Genealogical Society Jamboree, 23andMe announced some new features for their Ancestry component. Here is a link to their blog post:

CeCe Moore has also covered this in a post to her blog:

A new My Ancestry Page; Ancestry Painting v.2 with 20 populations to compare against; Relative Finder Geographic Map View; and Family Tree with GEDCOM upload are among the changes.

It looks like some exciting improvements are coming this year.

Monday, June 04, 2012

Identified matches at FTDNA, Family Finder, and at 23andme, Relative Finder

I have 330 matches in Family Finder at FTDNA and have identified 13 relationships.

I have 1440 matches at 23andMe and am Sharing Genomes with 402. I have identified 15 relationships with those 402.

The success ratio at both services is comparable at about 4%.

I also have matches at GEDMATCH, but I have not been successful in identifying the relationship with any one there who is not already identified in Family Finder or Relative Finder.

If you are in the 23andMe database, a new feature of Ancestry Finder allows you to compare all of your matches and their matches to see if there are clusters at common locations. See this post for details on a method to download all your AF matches and their matches and use a spreadsheet for triangulation of the results:

Saturday, June 02, 2012

Status of the Sorenson Molecular Genealogy Foundation, SMGF,genetic genealogy DNA Databases and GeneTree

Like many other people I participated in the Sorenson Molecular Genealogy Foundation, Y DNA, mtDNA and autosomal DNA testing program.  Recently some of the principal people involved in that program moved to and their DNA Ancestry program.  I wrote to the SMGF to ask about the status of their databases. With their permission, their reply is printed below :

Hello Steven,

Yes, the databases have been transferred to GeneTree will not be continuing; they have stopped taking orders and in the near future will be taken down. There are not plans to automatically 'convert' GeneTree accounts into accounts, so GeneTree customers will need to move their information over to Ancestry on an individual basis.

As far as the autosomal database is concerned, our autosomal tests were generated with older technology, making them incompatible with current industry standards. Therefore, they are not included in the autosomal service offered by AncestryDNA. We also don't plan on making them available via
Best regards,


As of today, 1 June 2012, the Y DNA and mtDNA databases are still available at the SMGF site: If you have tested I suggest you go and download your results and your matches. It is my understanding that people will be able to remove their results from the databases if they so desire.