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DNA

  • DNA testing is constantly changing and improving.
  • DNA testing is all about the size of the database. The more information it has to compare your information to, the better results you will get.
  • Although a potentially powerful tool, DNA testing rarely provides an immediate answer. Traditional genealogical research is still necessary and important to connect generations.

  • International Society of Genetic Genealogy Wiki provides ansers to common genetic genealogy questions.
  • This Ancestry blog discusses some of the interesting finds you can make through a DNA test.
What is DNA?
  • DNA is a complex molecule that is found in nearly every cell in our body.
  • DNA consists of two long chains of molecules joined together. The smaller molecules form pairs. These bonds and the order in which they are arranged determine personal traits such as eye color, hair color and height.
  • DNA testing looks at variations in a DNA sequence that builds a person's genetic profile.
  • DNA in every human being is 99% identical. Only 0.1% of your DNA is unique.
  • Each parent gives their child exactly half of their DNA, but the assortment of genes or markers is unique to each child.
Types of DNA tests
  • Autosomal
    • Provides you with a breakdown of your genetic ethnicity by comparing your DNA with the DNA of those around the world. Genetic signatures help predict where ancestors once lived.
    • This test is not gender specific, it can access both sides of your family.
    • There is nothing in this test that will tell you which branch of your family a match is on. Therefore, having other family members tested will give you more information to work with.
    • Matches are based off of over 700,000 markers from your entire genome.
    • Testing companies provide the total amount of DNA - measured in centimorgans CM - shared with each genetic match. You can estimate a relationship based on the number of shared CM's. A good chart to estimate relationships is available at Autosomal DNA Statistics
    • This test currently allows you to find cousins across any of your ancestral lines who shared an ancestor within the last five generations.
    • The greater the generational distance, the less likely it is that autosomal DNA will identify potential ancestors
  • Y-DNA
    • Looks at your direct paternal lineage through your Y chromosome.
    • Shows your paternal migration path from thousands of years ago.
    • Available only for males.
    • There are Y-DNA surname studies, which can help you identify potential ancestors.
  • mtDNA
    • Looks at your direct maternal lineage through your mitochondrial DNA.
    • Shows your maternal migration path from thousands of years ago.
    • Available for both males and females.
    • Mothers pass mitochondrial DNA to both male and female children, however only female children pass the mitochondrial DNA to their children.
Places to Test
  • Note: The size of the database is vital for DNA research. The larger the database, the more information the company can offer. This means that you have a greater chance of connecting to cousins and ancestors.
  • 23andme
    • Tests include: Y-DNA testing and mtDNA testing.
    • Now integrated with MyHeritage.
  • Ancestry DNA
    • Autosomal testing only.
  • DNA Gedcom
    • Allows you to upload raw data from Family Tree DNA and 23andme in order to compare your results to a larger database.
  • DNA.Land is a relatively new service that offers analysis of raw data from 23andme, AncestryDNA and Family Tree DNA.
  • Family Tree DNA
    • Tests include: Y-DNA testing, mtDNA testing and family finder (autosomnal DNA).
    • Has the largest Y-DNA database in the world.
    • Only company to offer full mitochondrial sequence.
    • Offers free webinars.
  • GEDmatch allows you to upload data from Family Tree DNA, 23andme and Ancestry to compare results.
    • Registration is free.
    • Contains a forum section where you can connect with other users.
  • Living DNA is a British site
    • It's ethnic breakdowns include 21 regions just in Britain
  • My Heritage now offers DNA testing through their website.