Using Autosomal DNA to Explore Your Ancestry

Blaine T. Bettinger November 16, 2013

“Using Autosomal DNA to Explore Your Ancestry”

- © Blaine T. Bettinger 2013

- Provided only to members of the Western New York Genealogical Society (WNYGS)

- Please do not share, modify, or distribute without permission from the author.

For more information:

- The Genetic Genealogist

- 23andMe - Family Tree DNA - AncestryDNA

- “Trace Your Roots with DNA: Using Genetic Tests to Explore Your Family Tree” by Megan Smolenyak Smolenyak and Ann Turner

Helen Marley Johnson

- b. 3 March 1889 in Mexico, NY

- d. 26 Feb. 1983 in Watertown, NY

- Parents?

Autosomal DNA and My Great-Grandmother’s Mystery

Autosomal DNA and My Great-Grandmother’s Mystery

DNA • “Blueprint for life”

• 23 pairs of chromosomes: o 22 pair of autosomal DNA o 1 pair of sex chromosomes

• Mitochondrial DNA

mtDNA

Types of Genetic Genealogy

• Y-DNA (the Y-chromosome)

• mtDNA (the mitochondrial genome)

• Autosomal DNA (the non-sex chromosomes)

• X-DNA (the X-chromosome)

Y-DNA and mtDNA tests ignore 95% of the DNA in the cell:

mtDNA

Autosomal DNA

Inheritance of Y-DNA

The surname follows the Y-DNA!

Inheritance of mtDNA

The mtDNA travels down the maternal line!

Me

• You have BOTH a genealogical family tree and a genetic family tree:

–Genealogical Tree - contains all of your ancestors

–Genetic Tree - contains a tiny fraction of your ancestors (only those ancestors that randomly contributed to your DNA)

Your Genetic Family Tree

128 ancestors at 7 generations

<<<128 ancestors at 7 generations

Graham Coop, Ph.D.

• Genetic Tree:

- At 7-9 generations, genealogical ancestors fall off the Genetic Tree

- Only about 475 of 1024 ancestors (or 46%) at 10 generations!

- The majority of your ancestors did NOT contribute to your DNA!

(Thank you to Luke Jostins and Graham Coop)

Your Genetic Family Tree

• Genetic Tree:

- Since your genetic tree is randomly inherited from your parents, even siblings will have different genetic trees!

- (except identical twins)

Your Autosomal DNA

Significant contributions to Genealogical Tree can be missing from your Genetic Tree:

Graham Coop, Ph.D.

Significant contributions to Genealogical Tree can be missing from your Genetic Tree:

Why Test?

Reason #1: Biogeographical Estimates

Why Test?

Biogeographical Estimates

» Aka “Ethnicity”

» Proprietary algorithms match segments of your DNA to reference populations from all around the world

» Results are reported as percentages of DNA that aligns with each of the reference populations

Biogeographical Estimates

90%

10%

10%

90%

Result = AA

Companies Differ!

Estimates Change!

Estimates Change!

Biogeographical Estimates

• The Bottom Line:

- Companies use different methods to derive estimates – so estimates differ

- Companies refine the methods used to derive estimates – so estimates change

- Don’t take your estimate to the bank…

Reason #2: Finding Genetic Cousins

Why Test?

Yes, You Share DNA With Your Family…

Finding Genetic Cousins

• Company compares your DNA to the DNA of all other test-takers in the database

• Predicted cousins are identified

• Relationship Range is provided based on factors such as:

» Total % of DNA shared

» Size of segments shared

Good News!

Finding Genetic Cousins

• How reliable are relationship predictions or ranges?

• VERY reliable through 3rd or 4th cousins

• Difficult to predict a 5th cousin versus a 10th cousin (since both will share so little DNA)

What is the probability that my relative and I share enough DNA to be detected by

DNA Testing?

I have a match, now what?

• Step 1 – review the match’s profile for surnames and other information

• Step 2 – contact the match and ask if willing to share a family tree or have one online

• Step 3 – compare family trees (names, dates, locations, etc)

• Step 4 – identify potential common ancestors

Reason #3: Health Information

Why Test?

Risks and Inherited Conditions

Decreased Risks

Traits and Drug Response

Health Information

Can be very small risks

Not deterministic (not GATTACA)

The science is always changing with new research and developments

GINA

Reason #4: To Solve Genealogical

Mysteries

Why Test?

Helen Marley Johnson

- b. 3 March 1889 in Mexico, NY

- d. 26 Feb. 1983 in Watertown, NY

- Parents?

Autosomal DNA and My Great-Grandmother’s Mystery

• mtDNA was not helpful

• Can I use autosomal DNA to identify Helen’s parents?

Autosomal DNA and My Great-Grandmother’s Mystery

Autosomal DNA and My Great-Grandmother’s Mystery

First Cousins

Any shared DNA will have come from Helen and her husband!

Testing Procedure

• Use the living to recreate a lost genome:

– Test my father’s autosomal DNA (grandchild of Helen)

– Test Living Walton’s DNA (grandchild of Helen)

– Find shared DNA

These shared stretches of DNA were shared by siblings Roy and Esther Bettinger (from their parents) and were passed down to the next generation

Autosomal DNA and My Great-Grandmother’s Mystery

• I’ve identified DNA from Helen and Frank, now what?

– Identify shared relatives

– Explore shared relatives’ genealogies

– Look for clues as to Helen’s ancestry

•Johnson surname?

•Located in the Oswego Co, NY area?

Autosomal DNA and My Great-Grandmother’s Mystery

• The “In Common With” Tool:

Autosomal DNA and My Great-Grandmother’s Mystery

It works!

But…

Autosomal DNA Summary

• Key Points:

• Everyone has a Genealogical Tree AND a Genetic Tree!

• Useful for:

- Biogeographical estimates

- Identifying genetic relatives

- Attacking mysteries

$99

(Autosomal, Y-DNA and

mtDNA SNPs)

(& medical!)

$99

(Autosomal DNA)

$99 for Ancestry.com

subscribers (Autosomal DNA only)

$199.95 (Autosomal

DNA)

Testing Companies

Free $100 Restaurant.com Gift Card (until 12/31/13?)

Quick and painless:

• A test will not return a complete family tree (yet!)

• Only examines a small percentage of your genealogy (1024 ancestors at 10 generations)

• DNA can reveal long-hidden secrets

–NPEs (adoption, infidelity, name change, etc)

Issues to Consider…

blainebettinger@gmail.com

www.thegeneticgenealogist.com

Questions?