GENETIC GENEALOGY: USING DNA AS A TOOL IN GENEALOGY © 2014 SHANNON COMBS-BENNETT

Genetic Genealogy: Using DNA as a Tool in Genealogy

Presented by Shannon Combs-Bennett

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Why should I do this? This is the one question I am frequently asked when people find out I know a little about DNA testing and genealogy. Frankly, it is a personal decision. Your reasons may be different from the person sitting next to you, but usually the common thread is you want to know more about your family and trying to knock down a brick wall.

Genetic genealogy has taken off in the last decade as DNA sequencing and access to testing has become easier and more affordable. As with all new technical advances it has had its growing pains but is now a mainstay in the savvy genealogist’s toolbox. As with everything we do in genealogy, DNA testing is a tool. It will not give you definitive answers to your heritage, but give you clues. Coupled with paper genealogical research it can help validate possibilities. DNA has led to more than one person validating a hunch and proving a connection that was only theoretical on paper.

Many people refuse to do DNA testing because they are afraid that insurance companies, the government, or their employer may be able to use that information against them. In 2008 the US Government passed the Genetic Information and Non-Discrimination Act (GINA) so that this will not happen. Right now the only people who have access to your DNA results at the genetic genealogy testing centers are you and those you give permission to. Your employers and your insurance companies cannot access this information. For further details you can read about GINA here: www.genome.gov/10002328.

Genetics, just like genealogy, has its own language. Understanding the words and their meaning makes a large difference in the amount of information you can get out of your results. Below is a listing of genetic (and genealogy) terms that you will need to know.

• Allele: specific form of a gene, one of multiple possibilities. In genetic genealogy used as the

reference for a marker. • Chromosomes: structure in the cell where genes are located. • DNA (Deoxyribonucleic acid): a molecule that contains the genetic instructions for living

organisms. • Gene: a unit of heredity in living organisms. One gene may have multiple forms, or alleles,

defined by different DNA sequences. • Genome: the collection of genes in an organism • Haplogroup: genetic population who share a common ancestor on the paternal or maternal line

with similar SNP mutations. • Haplotype: the set of numbers that make up your genetic testing results. • MRCA: Most Recent Common Ancestor, the closest direct line ancestor shared between

descendants. • Locus: physical location of an allele on the chromosome. • Marker: the specific place on a chromosome with two or more forms. The inheritance of it can

be followed through each generation. • Phylo-tree: Phylogenetic Tree is the reference diagram that show all the haplogroups.

GENETIC GENEALOGY: USING DNA AS A TOOL IN GENEALOGY © 2014 SHANNON COMBS-BENNETT

• Proxy: the contact person for the DNA test if not the person taking the test. • SNP: Single Nucleotide Polymorphism, a small amount of DNA tested which confirms your

haplogroup by identifying if it has mutated from the ancestral state. • STR: Short Tandem Repeat, the number of repeats of a base pair sequence which then

determines the marker value. • Sub-clade: an offshoot branch of the phylo-tree or a reference to deep clade testing.

There are three main types of DNA tests, with a fourth just making its debut into testing options this past year. They are Autosomal DNA, yDNA, mtDNA, and now xDNA. You can get a clue as to which part of the DNA is tested by the word or abbreviation before DNA. Autosomal DNA, also known as admixture DNA, is the non-sex-determining chromosomes in a person’s cell. yDNA is only for men as it tests the Y-chromosome found in males. mtDNA can be taken by anyone and will trace their maternal ancestors. Finally xDNA tests trace a person’s X-chromosome and can be taken by men and women.

There are quite a few testing companies for a genealogist to choose from. The most used testing companies are Family Tree DNA (FTDNA), 23and Me (currently not testing), Ancestry DNA through Ancestry.com, and National Geographic Genographic Project. To help you make an informed decision on which company can proved the service that you desire Tim Janzen has created a DNA Test Comparison Chart found at this link: www.isogg.org/wiki/Autosomal_DNA_testing_comparison_chart

Below is a small portion of the resources available to you on this topic. I encourage you to read, explore, ask questions, and most of all have fun with this new tool in your tool box. It can open doors for you in your research. All you have to do is take the first step.

Websites

• Genetics Home Reference ghr.nlm.nih.gov/ • DNA Interactive www.dnai.org/ • International Society of Genetic Genealogists (ISOGG) www.isogg.org/ • ISOGG Wiki www.isogg.org/wiki/Wiki_Welcome_Page • Guild of One Name Studies www.one-name.org/

Blogs

• Your Genetic Genealogist by Cece Moore www.yourgeneticgenealogist.com/ • The Genetic Genealogist by Blaine Bettinger www.thegeneticgenealogist.com/13/ • DNAeXplained by Roberta Estes dna-explained.com/ • On-line Journal of Genetics and Genealogy jgg-online.blogspot.co.uk/

Books

• Terrence Carmichael and Alexander Kuklin. How to DNA Test Our Family Relationships. DNA Press, 2000

• Colleen Fitzpatrick and Andrew Yeiser. DNA and Genealogy. Rice Book Press, 2005 • George Redmonds, Turi King and David Hey. Surnames, DNA and Family History • Megan Smolenyak and Ann Turner. Trace Your Roots with DNA: Using Genetic Tests to Explore

Your Family Tree. Rodale Books, 2004