Let’s talk about the different “kinds” of DNA and how they can be used for genetic genealogy.
It used to be simple. When this “industry” first started, in the year 2000, you could test two kinds of DNA and it was straightforward. Now we’ve added more DNA, more tools and more testing companies and it’s not quite so straightforward anymore. But’s it’s a LOT better for genealogists.
Four Kinds of DNA
There are 4 different kinds of DNA that genealogists can use to provide information about our ancestors.
1. Y DNA for males only – Family Tree DNA tests the Y chromosome which is passed from father to son, along, in most cases, with the surname. Only men can take this test, because only men have a Y chromosome.
Female genealogists need to ask their fathers, brothers, uncles and male cousins to test for the surnames in question. You can read the article, Concepts – Who to Test for Your Father’s DNA.
Family Tree DNA compares the results of the Y chromosome test between males to see if they match and are related in a genealogical timeframe.
Testers also obtain their haplogroup which is a genetic clan and tells your ancestral story of deep ancestry, such as European, African, Asian or Native American heritage.
Family Tree DNA sponsors free surname, haplogroup and other special interest projects, such as American Indian or regional projects. Projects are indispensable for both genealogy and genetic genealogy research and everyone can join.
Family Tree DNA is currently the only testing company that offers Y DNA testing providing matching, projects and other tools, including the advanced Big-Y test. Y DNA test levels include 37 and 111 markers in addition to the Big Y-700 test which provides a minimum of 700 markers and extremely granular advanced haplogroup testing.
Testing more markers is how one determines who they are related to most closely in time. The Big Y-700 is definitely the best test, but the 37 and 111 marker tests can be considered entry-level. The Y DNA test is great in combination with the Family Finder autosomal test, and advanced matching allows you to see who you match on both tests.
You can read more in my article, Working with Y DNA – Your Dad’s Story.
2. Mitochondrial DNA for everyone – Mitochondrial DNA tracks your matrilineal line and is passed generationally from mother to mother to mother to both genders of her children, but only females pass it on.
Males carry their mother’s mitochondrial DNA but they don’t pass it to their children.
Like Y DNA, mutations are compared to see if testers share an ancestor in a genealogical timeframe, but because the surname changes in every generation, it’s more challenging genealogically to make the connections.
Mitochondrial DNA testing also provides a haplogroup which defines deep ancestry, such as European, African, Asian or Native American.
Family Tree DNA offers free haplogroup and other special interest projects such as the AcadianAmerindian Project.
Family Tree DNA is the only testing company that tests mitochondrial DNA and provides matching, projects, and tools.
You can read my 4 part series about mitochondrial DNA beginning with the first article:
Autosomal DNA is inherited from all of your ancestors shown in the pedigree chart above, and further back in time as well. Y DNA and mitochondrial DNA are extremely important to inform us about the specific ancestry, both near and deep, of one line each, while autosomal DNA provides us with a different type of information about a wide range of ancestors.
In addition to Family Tree DNA who provides testing, mitoYDNA, a non-profit has begun accepting transfers for matching. Additionally, both WikiTree and Geni allow users to associate Y and mitochondrial DNA with specific ancestors.
While Y DNA and mitochondrial DNA are never recombined with the DNA from the other parent, you do receive half of your autosomal DNA from each parent. Autosomal DNA is recombined in each generation, so each new generation inherits less DNA from previous generations.
The inheritance paths for autosomal DNA are shown below. You can see that this includes all of the various ancestral lines, including the lines that also contribute the Y-line and mitochondrial, but those are separate and different tests providing different kinds of information.
Autosomal DNA tests are provided by:
You can order an autosomal DNA test by clicking on the vendors’ links, above.
These tests provide ethnicity estimates and a list of cousin matches from all of your ancestral lines, but it’s up to you to figure out how these cousins are related to you. Various testing companies provide different tools to help in this quest, each having their own strengths.
All four companies provide the ability to download your raw data results so that you can perform further analysis by using several online tools, the most popular being GedMatch, DNAPainter, Genetic Affairs and DNAGedcom.
Many articles on this blog are devoted to working with autosomal DNA and is entirely keyword searchable for your convenience.
4. The X Chromosome – The X chromosome is included as part of autosomal DNA testing. The X chromosome has special inheritance properties that allow people to use these results separately from the rest of the autosomal results.
The 23rd pair of chromosomes defines your biological sex. If a father contributes his Y chromosome, the child will be male. If a father contributes his X, the child will be female. Mothers always contribute an X, because they don’t have a Y chromosome.
The inheritance path of the X chromosome is different for males and females, because males only inherit an X chromosome from their mother (and a Y from their father which makes them male), but women inherit an X from both of their parents. Therefore, an X match with another tester can eliminate several potential ancestors. For males, an X match must come from his mother’s side of his family.
You can read about X matching, along with a helpful X inheritance chart, in the article, Who Tests the X Chromosome?
You need to test before you can receive results to jump-start your genealogy.
I recommend that every genealogist do the following:
- Test your Y DNA or the Y DNA of your paternal lines by recruiting others
- Test your mitochondrial DNA
- Build a DNA Pedigree chart
- Test with or upload your autosomal DNA to all 4 vendors. Different people test at different locations. I have important matches at each vendor who have never tested elsewhere.
- Upload your autosomal DNA file to GedMatch for additional functionality. It’s free with Tier-1 advanced functionality requiring a subscription.
Family Tree DNA and MyHeritage accept uploads for free, with an unlock fee required for advanced tools. If you subscribe to MyHeritage, no unlock fee is required. You can begin a free trial subscription here.
Ancestry and 23andMe do not accept uploads, so you must test there directly. Ancestry requires an additional subscription for some functionality, such as seeing your matches trees and advanced features. Here are my 4 articles with instructions for how to download and upload your DNA file:
- Family Tree DNA Step-by-Step Guide: How to Upload-Download DNA Files
- MyHeritage Step-by-Step Guide: How to Upload-Download DNA Files
- Ancestry Step-by-Step Guide: How to Upload-Download DNA Files
- 23andMe Step-by-Step Guide: How to Upload-Download DNA Files
Have FUN! Your ancestors are waiting on you.
I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.
Thank you so much.
DNA Purchases and Free Transfers
- Family Tree DNA
- MyHeritage DNA only
- MyHeritage DNA plus Health
- MyHeritage FREE DNA file upload
- 23andMe Ancestry
- 23andMe Ancestry Plus Health
- Legacy Tree Genealogists for genealogy research