DNA testing is useful where parentage is unknown such as in the following cases:
Other situations where DNA testing is useful is where parentage is known but records are unavailable, and where the ethnic heritage of ancestors is unknown. It is generally useful in confirming that the ancestors found through researching your family tree are indeed your ancestors. If researching all the descendants of an ancestral couple, DNA testing may reveal additional relatives not found through the usual genealogical methods.
DNA inheritance is random. In the worst case scenario you may not have inherited DNA from a grandparent. In the best case scenario with autosomal testing you may be able to confirm ancestors going back eight generations. It should be noted that the further back you go through the generations the more likely you are to have a non-paternity event (NPE) or misattributed paternity; the incidence of this is said to range from 1% to 2% per generation.
The benefits of having an autosomal DNA test are twofold: an ethnic heritage estimate and a list of people who are DNA matches.
An autosomal DNA test is useful in providing an ethnic heritage estimate. This changes over time as the DNA companies' test groups become larger and from more diverse areas in the world. In addition to ethnic mix an autosomal DNA test can narrow down specific areas where one's ancestors have lived.
An autosomal DNA test will provide a list of people who are DNA matches. It will provide data on the amount of shared DNA for each person and an estimation of the degree of relationship. As the amount of people getting tested with the DNA company increases with time the number of DNA matches will increase.
Once you have DNA tested some DNA testing companies will for the payment of an extra fee, allow you to explore physical traits that you may have inherited. You can explore how your DNA influences fitness, absorption of nutrients, appearance, and sensory sensitivities and intolerances.
To maximize the number of DNA matches you can download your DNA test results from the original DNA testing company and upload it to other DNA testing company websites as well as the DNA comparison website Gedmatch.
Some DNA testing companies have chromosome browsers which using the DNA matches on their website, allow you to identify the areas of your DNA you have inherited from particular ancestors. Software packages such as DNA Painter also allow you to map your chromosones.
This is a sorting tool that groups your DNA matches into clusters; these are groups of DNA matches that are most likely to descend from a recent common ancestor.
AncestryDNA results include information about one's geographic origins across 1000+ regions and identifies potential relatives through DNA matching to others who have taken the AncestryDNA test. DNA test results are downloadable. AncestryDNA has the largest DNA database.
Living DNA also accept uploaded autosomal DNA tests from AncestryDNA, 23andMe, MyHeritage DNA and Family Tree DNA. Their Our ancestry test provides worldwide regional breakdowns, with five times the detail of any other DNA test on the market for African ancestry and eight times more detail for the British Isles.
MyHeritage DNA reveals your unique heritage - the ethnic groups and geographic regions you originate from. It will also assist you to find new relatives you never knew existed through your shared DNA. The tools on MyHeritage include a chromosome browser and AutoClusters, a clusters tool. MyHeritage DNA accepts uploaded autosomal DNA tests from other providers. MyHeritage DNA is said to be used more by Europeans and South Americans.
MyHeritage is giving a 5% discount on MyHeritage DNA to Victorian Genealogy users (Coupon code: victoriangenealogy).
Their Ancestry + Traits Service helps you understand who you are, where your DNA comes from and your family story. They analyze, compile and distill your DNA information into reports on your Ancestry Composition, Ancestry Detail Reports, Traits, Haplogroups, and Neanderthal Ancestry. They also provide a DNA Relatives tool to enable you to connect with relatives who share similar DNA, an automatic Family Tree builder and a chromosome browser. 23andMe has the second largest DNA database.
Family Finder DNA Test includes
FamilyTreeDNA also includes a chromosome browser. It accepts uploaded autosomal DNA tests from 23andMe, AncestryDNA and MyHeritage DNA.
With the myDNA Personalized Wellness service, you'll receive insights related to your health and wellness all based on your DNA.
Gedmatch is a US online service to compare autosomal DNA data files from different testing companies. GEDmatch users could upload their autosomal DNA test data from commercial DNA companies, with or without a GEDCOM file, to identify potential relatives who have also uploaded their profiles. Tools available on the GEDmatch site included sorting results by the closest matches to a user's autosomal DNA, whether one's matches match each other, genetic distance calculator, estimated number of generations to a common ancestor, whether one's parents are related, and an ethnicity calculator. It also includes a chromosome browser and clusters tool.
DNAGedcom is a third party tool used by genetic genealogists. The tools and documents are primarily for the use of adoptees looking for birth family.
DNA Painter is a tool that helps genealogists make sense of DNA testing. By mapping segments of DNA to chromosomes, you can begin to see which ancestors gave you which pieces of DNA, and thus how new matches are related. It may be used with DNA matches from 23andme, FamilyTreeDNA, MyHeritage and Gedmatch.