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DNA – A simple explanation

Family History research can be mostly about the past, researching ancestors who have died. The usual method is to start with yourself, your parents, and work back through your pedigree to find your Great Grandparents. Once you have found them, then you can work back down again discovering all of the siblings in each generation. This research becomes much more difficult due to privacy restrictions for more recent generations but DNA testing can make these current generations much easier to contact.

What is DNA?

For this simple explanation, let’s consider our DNA to be like a fruitcake recipe. My GGG Grand Mother changed the standard recipe and added some port wine. This wine was a unique feature of her recipe, so her fruitcakes could be scientifically differentiated from the other fruitcakes. This secret recipe has been handed down through the generations so scientific analysis of fruitcakes could detect all cakes made by the family members – because they all contain port wine.

DNA is like a recipe because DNA is the basic building block of each of us. DNA is very stable but it can change on very rare occasions. These changes become a unique identifier. A DNA test looks for unique changes and then groups all people who have that particular unique change as a ‘DNA match’ or a possible family member  – because once the DNA changes, that change will be passed down through future generations.

How is a test done?

There are 2 main types of test but both are designed to be done at home. One test is done by spitting into a tube. The kit has a plastic tube with a small funnel so you simply dribble some spit into the tube. The other test is a swab that you wipe around on your cheek. Both are very quick and easy.

How do I find a DNA Match?

Once you have done the test, it is mailed back to the laboratory and your test results are posted online. There is no point in posting the print out to you as it would be meaningless anyway. It would just be a lot of A, C, G, and Ts. These letters represent the four chemical building blocks, adenine (A), cytosine (C), guanine (G) and thymine (T). The report would be a long list of these ACGTs in a strange but unique order. The value of the test results is revealed when we compare our test against a lot of other tests to reveal our ‘DNA Matches’.

Your DNA matches will be ranked in order based on the amount of your DNA that matches with the DNA of other people. Naturally, if your brother has NOT done a DNA test, then you will not have a DNA match displayed for him until he does have a DNA test result to compare against your result. This might sound silly until you start to consider which company you should do your DNA test with.

What company should I do my DNA test with?

The chance of finding more matches is raised when you increase the number of DNA tests that you compare against. I, therefore, suggest that you test with the company that has the most DNA tests to compare against, and that is currently (in 2018) a company called Ancestry.com who has over ten million tests in their database. Ancestry.com does not allow you to upload a test to their database so the only way to get your test into their database is to do the test with them. These numbers change as the popularity of DNA testing is growing exponentially. For example, Ancestry is reported to have taken 200,000 DNA test kits to an expo and they sold out.

There are several other companies that do DNA testing but their database is smaller. These smaller companies also allow tests from other companies to be uploaded into their database (mostly for free) as they also want to be the biggest database. Ancestry currently allow a user to download their test result, and this can then be uploaded to other sites to increase the number of comparisons, and therefore, increase the number of possible DNA matches.

How do I contact a DNA match?

Once you have your DNA results available, you will also see those users who match with your test. You will be able to contact these people to see if you are related. It is helpful if you both have a family tree prepared as you will be able to look back to find your most recent common ancestor to confirm how you are related. This can help you both as you can both add the ancestors and their descendants to your family tree.

Who should do a DNA test?

Generally speaking, the oldest family member should be tested but several family members make the test results more powerful. We all get 50% of our DNA from our mother and 50% from our father. Siblings do not get the same 50% so one sibling can match more strongly with a certain ancestor. Having a mother or father tested as well as a child can also be helpful to determine where a match is on your tree. For example, if a child matches with a DNA test but the mother does not match, then that match is in the child’s father’s family.

This blog is a simplified explanation of a complex subject. It is not intended to be scientific but more as a simple beginners guide. There are many advanced steps that have not been covered here, such as the difference between the three DNA tests, Autosomal, Y DNA and Mitochondrial.

I hope it helps you to understand a little better but please contact us if we can assist in any way. We offer assistance in all stages of family tree research and this includes assistance with all stages of the DNA test process.

Contact Bruce today.


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