Triangulation vs. “In Common With”

This question came up in one of the posts in Blaine Bettinger’s Facebook Group Genetic Genealogy Tips & Techniques, so I thought I’d give a quick example here that I refer to myself when I get confused.

A man with 3 children, who have all tested, has a match to a 2nd cousin (documented through now through both DNA and traditional genealogy).  He and the 2nd cousin share 11 segments of DNA.

It so happens that all 11 of those segments have passed down to those 3 children, which you can see in the illustration below.  Of those 11 segments shared by their father and his 2nd cousin, Child 1 inherited 4 segments.  Child 2 also inherited 4 segments — but an entirely different four segments than Child 1.  Child 3 inherited 7 of the 11 segments.

The inheritance and sharing is illustrated below, in data pulled from GedMatch.

Inheritance

For purposes of illustration, we’re setting aside the fact that generally, when triangulating to find a common ancestor, we don’t use two full-blooded siblings as 2 of the triangle legs; they are too closely related, and will triangulate on many segments.

That said, Child 1, Child 2 and their 2nd cousin once removed (2C1R) have DNA in common with each other, but no triangulated segments with their 2C1R.  This is because Child 1 shares DNA with 2C1R on chr 6, on chr 12 and 2 segments on chr 15, while Child 2 shares DNA with 2C1R

Child 1, Child 3 and their 2C1R have 3 triangulated segments: on chr 6, on chr 12, and 1 segment of chr 15.

Child 2, Child 3 and their 2C1R also have 3 triangulated segments: on chr 4, on chr 8, and on chr 18.

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And that is a quick overview of triangulation vs. in common with.

 

 

The Shared cM Project: Tracking individual contributions

Do you know about Blaine Bettinger’s Shared cM Project?  It’s the crowd-sourced collection of shared centiMorgans (cMs) for the purpose of analyzing the ranges of cMs found at different levels of relationship (full siblings, half 1st cousins, 2nd cousins, etc.)

If you and your known relatives have done your DNA tests at any of the big vendors, you can submit your data here.  Relationship is asked for, but no identifying information (except your email) is needed for submission.

I have been submitting my own DNA data since 2016 — Blaine released the first results in May 2015.   However, so that I won’t skew the results (with duplicate or triplicate submissions), I keep track of my submissions in my own Excel spreadsheet.  A sample of the page I use is below, filtered on just some of the 2C1R relationships I have submitted.  (I have hidden the names of the two testers involved in each relationship.)

Submission_Shared cM Project

Note that the cM range for my submissions of 2nd cousin 1 removed is from 32 cM to 267 cM.  The vast majority of relatives at this level were known beforehand, or otherwise targeted tests.  In the case of the tester who only shares 32 cM, they share that cM with one of 1st cousins.  The rest of us — my siblings and I — and my 1st cousin’s siblings share a much more “typical” amount of DNA with the tester, around 110 – 140 cM.  And since we all match at the full-sibling level, and at the full 1st cousin level, it (so far!) appears that the 32 cM is just due to the randomness of DNA inheritance.

One thing I did in the beginning was submit a relationship for each vendor.  (My father, for example, has tested at 23andMe, FTDNA, and Ancestry, as have I.)  So, originally, I submitted 3 different sets of father/daughter data.  (Obviously, the cM count varied in only minor amounts.)

Since mid-2017, though, I only submit once no matter how many places the two testers have tested at.  (Blaine does ask for the vendor name when you submit.)

In general, I have said no endogamy — but that is based on what I know of the relationship.  Who knows?  With enough research on certain lines, I may find that indeed there was endogamy.

I also, for my own interest, track “expected” DNA shared with actual DNA shared (assuming grandparents and uncles/aunts share an average of 25% with the tester, first cousins share an average of 12.5%, 1st cousins removed (1C1R) 6.25% and 2nd cousins 3.13%.)  It never fails to amaze me how my sister, brother and I have such variations in the amount of cM shared with a given targeted cousin.

How do you track your submissions, if you are submitting to the Shared cM Project?  Are you concerned with not submitting twice — or do you figure it will all average out in the end (certainly a possibility)?

Cite/link to this post: Cathy M. Dempsey, “The Shared cM Project: Tracking individual contributions” Genes and Roots, posted 31 Mar 2019 (https://genesandroots.com : accessed (date)).

 

My review of the B.U. Certificate in Genealogical Education course

This past fall I took the Boston University Certificate Program in Genealogical Research.  This is a 15-week online course (for continuing ed credits only — NOT undergrad academic credit) taught by experts and professionals in the field of genealogy. 

The program was updated and modified with my class (Fall 2018).  It now has 4 modules:  (1) Genealogical Methods (5 weeks); — taught by Allison Ryall
(2) Evidence Evaluation & Documentation (4 weeks); — taught by Julie Michutka
(3) Forensic Genealogy (4 weeks);  — taught by Melinde Lutz Bryne, CG, FASG
(4) Genealogy as a Profession (2 weeks). — taught by Angela Packer McGhie, CG

Assignments were due each week, and were graded.   In addition, you are expected to log on regularly, and to participate regularly in discussions that are part of each module.  You need a grade of C or better in each module, and a B- overall to attain your certificate.  (Note: this is just a certificate.  It does NOT mean you are a Certified Genealogist through the Board for Certification of Genealogists.)

Getting on to what I thought of the course, I loved it!  It was well worth the cost (close to $2,700 — but I got 10% off, as I am a member of National Genealogical Society).  I did NOT take the 7-week Essentials course suggested by BU in advance of this course, deciding instead to just take the plunge.  I definitely needed a minimum of 20 hours per week to get through this course — but some weeks were more intense (citations!) and other weeks were “easier” (for me, that was the first module).

While I can’t make specific remarks as to the course content, my suggestion is that you are best off in the first module if you are familiar with a wide variety of records and have a high-level understanding of how DNA matches play into genealogical research.with DNA.    The module on evidence and citations has a new textbook — Thomas Jones’ Mastering Genealogical Documentation.  You are taught the art of citing your sources by understanding the source itself and the information within it — so you won’t have to just refer to templates.

The Forensic Genealogy module includes a focus on Ethics, since ethics play a significant role in dealing with living people, as far as DNA research and (financial) inheritances are concerned.  Finally, the module of Professional Genealogy covers the basics of what it takes to be a professional genealogist, using the brand-new Professional Genealogy: Preparation, Practice & Standards (published in 2018).

I found all the instructors (and their assistants) to be extremely responsive to my fellow students and myself.  I also thought the interaction between the students via discussion forums to be extremely helpful, learning as much from my classmates as from the coursework itself.  (The interaction between classmates is limited to the group you’re in, however; there were enough enrolled students for Fall 2018 that the students were divided into 2 sections, and further divided into 5 subsections of roughly 25 students each.)

All in all, if you want to ramp up your genealogical research skills very fast, this is a great course in which to do it.  Be prepared for a “grind” — you’ll likely need those 20+ hours a week to work on the readings and assignments.  There were about 4 or 5 in my own subsection of roughly 25 students that apparently dropped out before the end of the first module.  Afterwards, if you earn your certificate, you can choose to join the alumni mailing group (which includes alumni from all the past classes, back to 2009); a Facebook group exists as well.

 

Genealogy Goals for 2019

I’ve never been one for rigid goal-setting, or resolutions. (Hey, my Myers-Briggs type is INFP — and we “P” people like to keep our options open!)

That being said, I’m in a fairly unstructured time in my life right now; a little structure will keep me focused. And the cherry on top is to post my plans here.

Here’s to an awesome 2019! Happy New Year!

Education and Development Comments
BU (online class) for Certificate of
Genealogical Research
completed Dec. 2018
IGHR (Athens, GA) week of July 21, 2019;
registration opens 2 Mar 2019
Texas Institute of Genealogical
Research 2019
week of June 9, 2019
Legacy Tree webinars focus on BCG-sponsored
Community and Colleagues  
join Assn of Professional
Genealogists
done!!
renew Indiana Genealogical Society membership done!!
renew NGS membership done — 2 year renewal
join Tx State Genealogical Society done!!
start attending DGS meetings and
DNA SIG meetings
attend meetings regularly in 2019
Writing (high-level)  
Evaluate: what do I know and
how do I know it?
for key (aka “brick wall”) ancestors
Formulate a research question and a research plan for each of the
“brick wall” ancestors (above)
 
Write up GPS proof summaries (or narratives) for each research question I’ve asked (and think I’ve answered) re: my ancestors’ lives  
DNA  
Continue mapping my
chromosomes
my favorite thing!
Copple (family line) project  
Ask other cousins if they will
consider testing
 
Long-Range  
submit my lineage to Sonoma
County Genealogical Society for a
certificate (if approved)
by the end of 2019
submit an article to NGSQ this is at least a year away
get my CG designation — or my AG designation this is at least a year away
enroll in and complete ProGen
study course
typically a 6 month wait list, after
you enroll. Offered 3 x a year.