Testing to discover relatives and the origin (atDNA)
While testing of mtDNA and Y-DNA results enable discovery of deep ancestry, testing of autosomal DNA can give matches up to 6 generations back of the donor (last 150-200 years). In choosing a donor it is very important to find the oldest living ancestor and ask him/her to give a biological sample. He/she is much closer to a genetic and geographic origin of source population than people born as the third or fourth generation in the USA due to recombination of DNA and increasing number of ancestors at passing every generation (See Figure 1 and Figure 3). In more places, two donors match and longer sequences match, the higher is the probability that they are cousins.
There are many atDNA test providers, since the newest SNP array chips have been developed, but they rarely give good genetic genealogy services. If Slovenian DNA pool wants to benefit from largest genetic genealogy database, the Family Tree DNA services should be used. Results from testing in other laboratories can be imported, i. e. your autosomal DNA raw data file has to be downloaded from 23andMe©, AncestryDNA™, or MyHeritage™, and transferred to Family Tree DNA profile. After transferring the autosomal data is uploaded to the Family Tree DNA database and an access to Family Finder – Matrix is enabled for free, to receive a list of autosomal matches. The Matrix feature allows selection and comparison of the autosomal DNA relationship between up to ten matches at one time.
For those, who have not yet tested autosomal DNA, a test known as Family Finder can be ordered. This test is designed to find relatives on any of donor’s ancestral lines within the last five generations by male or female line (see figure 1). At the same time, Family Finder gives you a breakdown of your ethnic makeup by percent (myOrigins) by comparing your DNA to reference populations around the world that have been tested through scientific research, especially archaeological, going back in time for last 50,000 years.
Reference populations in myOrigins belong to twenty-four clusters based on a reference dataset pruned of related individuals in FTDNA database and using the Admixture package’s model, taking into account also ancient migrations and admixtures. Results of this model can be explored within a profile you get at Family Tree DNA. In case one would like to explore different population models and get more matches from people, who tested by another provider, results of atDNA testing and/or genealogical data (GEDCOM file) could be uploaded to the GEDmach portal. GEDmatch provides DNA and genealogical analysis tools for amateur and professional researchers and genealogists.
Table 1: List of world’s reference populations used in myOrigins.
 Razib Khan, Rui H, 2014, Family Tree DNA myOrigins Methodology Whitepaper. Updated Sept. 13, 2017