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Ancestry DNA Testing for family history: Demystifying how it works

In a series of blog posts, we’re exploring AncestryDNA tests – how they work and what they can do for genealogists and their family history research. Click here to see last week’s edition.

The first step in the process is to order yourself a kit, available from AncestryDNA. When it arrives, you’ll find instructions, a saliva collection tube and a pre-paid envelope. Taking the test is surprisingly simple: you only need to provide a small saliva sample and return it in the prepaid envelope.

After mailing your sample, it will take between six to eight weeks for the lab to process your DNA. Then keep an eye out for an email which will contain a link to your results – in the meantime, you need to activate your DNA kit online in order to begin processing.

How does it work?
The AncestryDNA test is an autosomal test that looks at an individual’s entire genome over 700,000 locations. Essentially, this kind of DNA test is capable of tracing both maternal and paternal lineage and any of your direct relatives between these two lines. Other types of DNA tests, such as Y-DNA and mtDNA testing, can only trace either paternal or maternal lineage, limiting the number of ancestors you can learn about.

Courtesy State Library NSW, ID hood_04442.
Courtesy State Library NSW, ID hood_04442.

Additionally, AncestryDNA’s autosomal DNA test provides information concerning the past few generations (from 500-1000 years). Unearthing details from this more genealogically relevant time period makes it easier to learn about more recent ancestors and connect with living relatives.

To do this, Ancestry takes your DNA sample and compares it against their database of DNA from people all over the world to find the common strands that help determine your ethnicity and where your ancestors were from. AncestryDNA then supplies your results in an easy-to-read map and pie chart that supplies your ethnicity estimates. The maps are interactive so that you can click around and zoom in for more details. The results may confirm your existing research – or perhaps raise further questions!

Interestingly, it is common for siblings to return different results. You receive about 50 per cent of your DNA from your father, and 50 per cent from your mother. However the segments of DNA that make up that 50 per cent are unsystematic – so ethnic breakdowns even between siblings can be quite different. The more people who take the test, the more information there is available.

Once you’ve received your results, it’s time to analyse what they mean. There are a number of tools available in AncestryDNA to interpret your results.

One of the great advantages of taking the AncestryDNA test is that your results connect to the enormous bank of information already collected by Ancestry. This includes the more than one million people who have taken the AncestryDNA test, as well as historical records and millions of family trees. As the database of DNA samples continues to grow, new information will arise, allowing greater insights into your results.


If you have an Ancestry account, you can link your DNA test results to your family tree through a new online interface. Importantly, you can also connect with the family trees of genetic matches (if they are public, or by request), find distant relatives and exchange information about shared ancestors.

Ancestry refers to these possible genetic living connections as ‘cousins’. How close a ‘cousin’ is, is determined through a ‘confidence rating’, which compares the amount of common DNA two people share. The higher the rating (between 1-100 per cent), the more likely it is that the two are closely related. If you and your DNA matches can share your family trees, often these connections can be illuminated by your research.

Managing your AncestryDNA account
If you are the person who purchases and activates your test on the website, then you are designated as the Administrator. This gives you control over who can see and access your results. You can give other users higher permissions to see your results or edit some of your information.

Courtesy ANMM, ID 2008/165/1-122.
Courtesy ANMM, ID 2008/165/1-122.

You can also elect to download your AncestryDNA data, or ‘raw data’. This is your test result before it is translated into the more usable information. Some users take their raw data to extend their research into other areas. There are tools available for analysing and comparing raw DNA data, however if you choose to upload your data to an organisation you need to check their privacy guidelines. Ancestry goes to great lengths to ensure that the raw DNA data of their users is secure and protected; you can read their privacy statement for more details.

DNA testing has been the frontier of family history for around a decade now and the technological developments of the last few years have delivered techniques that make DNA testing more accurate and meaningful than ever. The connection of this technology with Ancestry’s wealth of online resources, creates a powerful tool to help fill the blank spaces in your family’s story.

This is the second in our four-part series on DNA testing. Click here for the other posts in the series:

– Part One: AncestryDNA tests – An Introduction

– Part Three: Telling the story of your biological ancestors with AncestryDNA


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