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Home , 23andMe, Genetic genealogy

Discover Your DNA

What the most popular at-home genetic tests can tell you about your ancestry, ethnicity & health. What is DNA?

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every in a person’s body has the same DNA. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. ( Home Reference – National Institutes of Health – U.S. National Library of Medicine) Human DNA is in the form of 23 pairs of - 2 pairs of sex chromosomes (An XY pair in males and an XX pair in females) and 22 pairs of autosomal chromosomes. The <1% Difference

The <1% difference in the genetic makeup is comprised of and variations in the arrangement of bases within chromosomes. At-home genetic tests, like 23andMe, Tree DNA & Ancestry DNA, test for the variations in these bases on autosomal chromosomes, known as single polymorphisms (SNPs). SNPs occur normally throughout a person’s DNA. They occur almost once in every 1,000 on average, which means there are roughly 4 to 5 million SNPs in a person's . These variations may be unique or occur in many individuals; scientists have found more than 100 million SNPs in populations around the world. (Genetics Home Reference – National Institutes of Health – U.S. National Library of Medicine) Genetic Information Nondiscrimination Act of 2008 (GINA)

Federal law that prohibits health insurers and employers from using genetic information or family health history to discriminate against individuals, either through denying coverage, charging higher premiums or when making employment decisions. However, the Act does not apply to life insurance coverage. DNA Testing Company Comparison

Ancestry DNA FamilyTree DNA 23andMe Ethnicity Yes, but questionable Yes Yes accuracy Matches & Trees The most by far, but no X Yes, but trees can be Yes, but trees are very matches difficult to navigate limited Health No, but can be done No, but can be done Yes through a third party through a third party Sex Chromosomes No Yes, for an additional cost Yes

Chromosome Browser No, but can be done by Yes Yes uploading data to GEDMatch Messaging Yes, internal messaging Yes, utilizing email Yes, internal messaging What Can At-Home Genetic Tests Tell Me About My Health?

• Traits (e.g. – eye color, hair texture, ability to taste bitter, etc.) • Health Predispositions (e.g. – Macular degeneration, breast cancer, Alzheimer’s, Parkinson’s Disease, etc.) • Carrier Status (e.g. – Pendred Syndrome, Beta Thalassemia, Sickle Cell Anemia, Etc.) • Wellness (e.g. – Alcohol Flush Reaction, Caffeine Consumption, Lactose Intolerance, etc. Third-Party Health-Related Genetic Raw Data Interpreters

• LiveWello

• Promethease Why utilize third-party health genetic interpreters?

• Nutrigenomics

• Pharmacogenetics

• Genome Wide Association Studies (GWAS)

Identical by Descent (IBD)

DNA segments shared by at least two people that have been inherited by a common absent recombination. These segments are noted by a measurement called a centiMorgan. The number of centiMorgans shared is an indicator of the strength of the genetic match.

ISOGG Wiki Non-IBD Matches (False Positives)

Algorithms that are used by testing companies to match DNA produce a certain percentage of false positives by virtue of them not separating the maternal and paternal chromosomes when looking for matches on segments. Therefore, instead of of a matched segment being located on one chromosome reflecting an IBD match, the match may be a combination of segments on both chromosomes resulting in a non-IBD – false positive. This occurs more in segment matches under 10cM.

ISOGG Wiki Phasing

Phasing is the process of assigning to the maternal or paternal chromosomes. That permits matches to be assigned to the maternal or paternal line. To accomplish that, parents must be tested. Both, preferably. It is further refined by the addition of the results of children’s DNA being added. The more refined the phasing the less chance there is for false positive matches.

ISOGG Wiki Excess IBD sharing

There has been an abundance of IBD sharing on certain segments of some chromosomes noted in particular population groups. Some are related to the human immune system, while others seem to be the result of intermarriage within small groups, like the or French-Canadians. Algorithms at testing companies have been developed to limit the matches attributed to these segments; however, these segments are often used to help determine ethnicity by virtue of their being tied so closely to certain populations.

ISOGG Wiki

ISOGG Wiki

Triangulation

ISOGG Wiki

Genealogical Resources Testing & Websites: AncestryDNA www.ancestry.com 23andMe www.23andme.com FamilyTreeDNA www.familytreeDNA.com

Genomics Database w/ Chromosome Browser: GEDMatch https://genesis.gedmatch.com

Health & Wellness DNA Interpreters: LiveWello www.livewello.com Promethease https://promethease.com

Genetic Genealogy Websites & Blogs: International Society of https://isogg.org Kitty Cooper’s Blog blog.kittycooper.com Genealogical Musings genealogical-musings.blogspot.com

Adoptee Special Resources: DNA Detectives Facebook Page Search Squad Facebook Page DNA Adoption Facebook Page

Free Research Website: www..com

My Email Address: Holly Tolley [email protected]