Denise Manning, MLIS [email protected]

DNA & Genealogy: The Basics

Four Types of DNA for Genealogy – Three Types of Tests:

Autosomal (atDNA): Most every cell has 23 pairs of chromosomes. Half of each pair comes from dad, and half from mom. The 23rd pair are the sex chromosomes. Males receive Y from dad and X from mom; females receive X from both dad and mom. Purchase from: Ancestry, Family Tree DNA, 23 and Me, My Heritage, and Living DNA.

• Best way to fish in the most ponds: (prices change periodically)

 Test with Ancestry.com for $99.00 . Download Raw DNA Data, save zipped file on your desktop . Upload to FamilyTreeDNA.com for $19.99 . Upload to MyHeritage.com for $29.99 . Upload to GEDmatch.com (3rd party tool) for free . Upload to LivingDNA.com for $39.00  Test with 23andMe.com for $99.00

X DNA matches are provided with atDNA results by Family Tree DNA, 23 and Me, and GEDmatch.

Y DNA: Only males can test.

• Y DNA can determine relationships many generations back. • In many cultures, surnames follow Y DNA inheritance. • Purchase at FamilyTreeDNA.com

Mitochondrial (mtDNA): Outside the cell nucleus

• Females inherit mtDNA from mom, and pass it on to their children. • Males inherit mtDNA from mom, but don’t pass it on. • mtDNA mutates so slowly it is often not useful for genealogy. A shared ancestor could be hundreds of years in the past, long before a paper trail. • Purchase at FamilyTreeDNA.com

Ethnicity Estimate: Ethnicity results are the most fun, but the least accurate, part of atDNA testing.

• Testing companies compare our atDNA with test populations living today; not with our ancestors’ DNA. • Different testing companies use different test populations and different algorithms for comparison. • Some parts of the world have small test populations so those results can be quite general. • Testing companies are refining algorithms as test populations grow and the science develops.

Cousin Matching: Compare family trees to find your Most Recent Common Ancestor (MRCA)

• Prepare a GEDCOM file using your (, Roots Magic, etc.) • The more complete your family tree is (including birth dates and geography), the easier it will be to determine how your DNA matches connect. • Remember on-line family trees should be used only for clues. Many contain errors.

Centimorgans (cMs): measure the amount of atDNA you share with your match. The more cMs you share, the closer your relationship. (Find cM data on each company’s main atDNA match page.)

This chart is too small to read, but you’ll recognize it at the site below. Print a full- size copy or save it to your computer.

Blaine Bettinger’s Shared cM Project on the blog The Genetic Genealogist, https://thegeneticgenealogist.com/2020/03/27/ version-4-0-march-2020-update-to-the-shared- cm-project/

Shared Matches or In Common With: Each testing company offers a shared matches tool.

• Select a match and click “Shared Matches” or “In Common With” to view a list of people who share atDNA with you (the tester) and the DNA match you selected.

Additional Study:

Favorite DNA Books

• Blaine T. Bettinger, The Family Tree Guide to DNA Testing and [second edition] (Cincinnati, OH: Family Tree Books, 2019). • Debbie Parker Wayne, Ed., Advanced Genetic Genealogy: Techniques and Case Studies (Cushing, TX: Wayne Research, 2019).

Follow Some Blogs

• Blaine Bettinger (thegeneticgenealogist.com) • CeCe Moore (yourgenetic genealogist.com) • Roberta Estes (dna-explained.com) • Judy Russell (thelegalgenealogist.com

Favorite DNA Website & Wiki

• International Society of Genetic Genealogy (isogg.org) - Includes links to additional resources.

Study on FaceBook

• DNA Newbies • Genetic Genealogy Tips & Techniques • Search for pages combining DNA and geography like “Ontario, Canada DNA Matchfinder” • Search for surname pages like “Crowleys Around the World Uniting”