Understanding the
Autosomal DNA Test

The autosomal DNA test is the most cost-effective investment in genetic genealogy.

Each test checks a half million or more locations on your chromosomes.

Both men and women can take these tests and your matches can be from any branch of your family tree.

When the first autosomal DNA test came out, the price was several hundred dollars. Thanks to improved technology and much greater volume, prices have dropped dramatically. Now such tests cost less than $100 each.

As of now, four of these tests yield large numbers of genetic matches from huge user databases. Click each of the following links to learn more and see current pricing.

AncestryDNA 
from Ancestry

Family Finder 
from Family Tree DNA

23andMe 
from 23andMe

MyHeritage DNA from MyHeritage

While each test has different features and strengths, I recommend that adoptees and serious genealogists eventually do every recommended autosomal DNA test.

Why Do Every Autosomal DNA Test?

Since so many people take only one of these tests, the autosomal DNA test databases are quite different. There is no way to tell in advance which test will produce your closest or most useful matches. Now that you can get into all four databases for less than the cost of one test a few years ago, I encourage you to do so.

Adoptees should absolutely heed the advice of search angels to “fish in all the ponds.” While it is possible to identify your birth family from 3rd or even 4th cousin matches, it is much easier and faster if you can get a match that’s a 1st or 2nd cousin or even closer.

You need to exhaust every possibility of finding such a close match before you begin to work with more distant matches.

Uncovering Previously Unknown Relatives

Whether you’re a genealogist or an adoptee, the first function of genetic genealogy is to find previously unknown relatives. 

The testing company will compare your DNA with that of everyone else who has already taken the same test and will continue to compare you with new people who take the test for years to come.

If you and another person have several long segments of DNA in common, that outcome cannot be coincidental. You must both have inherited those segments from common ancestors.

The more segments you share and the longer the length of those segments, the more common ancestors you have...and the more closely related you are.

If your family has been in the U.S. for many generations, you are likely to discover hundreds or even thousands of matches.

Contacting cousins and/or reviewing their online family trees can get you beyond a genealogical brick wall or provide new information about shared ancestors.

Who Should I Test?

Testing yourself is the obviously place to start. But if one or both of your biological parents are living, you should test them too. Testing your parents has two important advantages:

First, your parents are one step closer to your family’s distant relatives. So, they will get some DNA matches that are too weak to show up in your results. 

Secondly, matches to your mother are clearly through your mother’s side of your family and matches to your father are clearly through your father’s side. If you only test yourself, it’s not easy to determine whether a match is from your paternal or maternal side.

Even if your parents are not available, testing additional known relatives on the same autosomal DNA test can help you sort your matches based on which testers have the match in common. So, the more family members you can test, the better. 

NOTE: If your family is part of an endogamous population, e.g. Ashkenazi Jews or Mennonites, where people tend to marry within a close-knit society, some of your matches will be related to your mother AND your father. This means that the projected closeness of the match may be overstated, i.e. a projected 3rd cousin may just be a 4th or 5th cousin with a lot of distant ancestry in common.

Powerful Tools for Adoptees

These key autosomal tests are helping adoptees overcome sealed records to discover and reunite with birth families.

The process can be remarkably easy or require quite a bit of work. It all depends on how close your matches turn out to be.

That’s why adoptees really need to get into every autosomal DNA database to exhaust every possibility of finding a close match.

If you’re lucky, you will get a direct match to a parent, aunt, uncle, sibling, or half sibling. This doesn’t happen for everyone; but it is becoming much more common as the databases get bigger.

Nearly as good is a match to a first or second cousin. By contacting that match and/or researching the person’s family tree, you can usually find a branch of your match’s family that lived in the time and place of your birth.

Even if your closest matches are third or fourth cousins, there is still a methodology that can uncover the truth of your origins.

Basically, you find two or more people who are genetically in common with you and each other…plus you all have overlapping segments on the same chromosome. Adoptees don’t yet have a family tree, but your matches probably do. And there’s a good chance that their common ancestor is your ancestor too.

You can use reverse genealogy to follow that common ancestor’s descendants forward in time to discover probable close relatives.

The complete methodology and information about tools to implement it more easily can be found here. This is the way to go if your autosomal DNA results don't yield any close matches.



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