DNA and family history are a match made in heaven – DNA is the biological story of your ancestry while the other is the narrative and facts of your ancestry (or your ‘ancestral story’).
But why and how?
The first thing to understand is why. DNA research can be a valuable tool for anyone at any stage in their research but proves to be of most value after a good solid foundation of research exists. This is because DNA research is most valuable in establishing relationships with others who have had their DNA tested – you may find a 3rd cousin! It would be hard to find out your relationship to someone the system says you might be related to (through similarities in DNA) if you don’t know your great grandparents names. Establishing these relationships can allow you to learn more about your ancestors as that distant relative may have completed some research you haven’t, they may have passed down family photos, relics or pieces of information and you can pool resources together to continue the research (such as funds, or working on different aspects of the research etc.). This can be valuable when you’ve reached a brick wall (a dead end in your research) – your distant relative may have already gotten past it!
Another way DNA testing can assist in your research is in providing estimated geographical information – your mitochondrial DNA (I’ll explain soon) may be quite common in China but not in England for example. This provides clues as to your distant (and likely unrecorded) ancestral origins. It sure proves interesting but can even help with brick walls.
So how? DNA is complex. But you don’t have to understand it totally to be able to understand how DNA testing can add another dimension to or assist your genealogical research! When getting your DNA tested there are different options – the ones most helpful for research and the most common options are mitochondrial DNA testing, y chromosome testing and autosomal chromosome testing. Mitochondrial DNA is a piece of DNA that is passed down only from female to female – males do have it but they simply do not pass it on. What this means is that your mitochondrial DNA has come from your direct maternal line (your mother’s mother’s mother’s mother’s mother’s etc. mother). This female person existed thousands of years ago! The people you connect up to in the database are people related to any of these women on your direct maternal line.
Another form of testing is y chromosome testing. The y chromosome is similar the mitochondrial DNA except it is passed down only from male to male. Getting this testing means you can find out about the ancient origins of your direct paternal line (your father’s father’s father’s father’s etc. father) and also connect you with others who are direct male descendants of any of these men in your direct paternal line. This is especially helpful if you have reached a dead end on your direct paternal line (the line with your surname) and also for clues in regards to your surname’s origins.
Another form of DNA testing is the testing of your autosomal DNA (FamilyTreeDNA – a testing company – calls this Family Finder). Autosomal DNA is the DNA that isn’t the x or y chromosome – you receive half your autosomal DNA from each of your parents. This form of testing will connect you up to many individuals however it can be hard to distinguish how they are related to you (especially if you haven’t done much research yet). However eventually you will connect with someone and exchange information – you may show them a thing or two you’ve discovered or they might tear down your brick wall in regards to your mutual great great great great grandfather.
It should be noted that all DNA undergoes mutations (slight changes) over time – these are taken into account when estimating relationships between others in the database. These changes happen so slowly however that you can find a distant cousin that matches up to you exactly even if they are very distantly related.