Everything you need to know about using DNA to trace your family history

Using DNA profiling to trace your family history has long become a reality with advances in DNA sequencing technology. There are dozens of Biotech companies who offer DNA sequencing services that help you learn about your personal history and ancestral information, thereby giving you the ability to trace your family history.

How Your DNA can Help You Trace Your Family History?

Your DNA can reveal a lot about your personal and family history, as the DNA is composed of genes that are inherited from your biological parents. Sequenced DNA can give information about the type of disease you are susceptible to, the color of your eyes and hair, your ability to learn certain things easily (like math), and even your ability to smell or taste certain things.

All your physical traits are summation of the genes you inherit from your parents. You have a 50-50 chance of inheriting each gene from your mother or father. If one parent carries the gene for brown eyes and the other for blue eyes, then you have an equal chance of inheriting brown or blue eyes, and in some rare cases, an amalgamation of both. If you have blue eyes and your sibling has brown eyes, then it just means that the genetic coin flip landed on one side for you and another for them.

Likewise, your parents both had a 50-50 chance of inheriting their parents’, your grandparents, genes. Therefore, you share 50% of your genes with your parents and 25% with your grandparents. This is how physical features and other family traits change (or sometimes stay the same) through the generations.

Higher frequency of similar genes point to a close familial relationship. Therefore, a DNA test can reveal how closely you are related to another individual. Full siblings share around 50% of their genes, while half-siblings share only about 25%. You also share about 25% with your aunts and uncles. First cousins share around 12%, second cousins share around 3%, and so on down the ancestral line.

All humans (Homo sapiens) share about 99.9 percent of the same sequence of DNA. Only about 0.1 percent of the sequence is different among various groups of humans. Regional populations of humans tend to share many of the same genetic markers. By comparing your DNA to a database of other individuals’ DNA sequences, genetic testing companies can give you an idea of where your ancestors came from.

It’s important to note that the information you get from a DNA genealogy test is general and probabilistic. That means the answers are based on statistical probabilities, and they aren’t to be considered as hard facts. While some genetic markers may be commonly found in one particular population, that doesn’t mean they’re unique to that people. It just means you’re statistically more likely to be related to those people than other groups.

But before you fork over more than $100 for such a test, you need to know answers to these question: Can a DNA test really tell me about where I come from? How do these tests work? And can they be wrong?

How to Choose a DNA Test?

The tests are widely based on three types of DNA source: autosomal DNA, mtDNA and Y-DNA.

1. Autosomal DNA offers the most extensive answers, with information regarding kinship and personal health. These tests can trace your lineage back to six or possibly even seven generations. Once the DNA is sequenced, the company matches your DNA to other individuals in its database and can help find “cousins”, individuals who share long strings of matching DNA and are likely to have shared common ancestors. In addition to ancestral lineage, this type of DNA test can also help identify physical traits and medical predispositions.

2. mtDNA (mitochondrial DNA) offers ancestry information through your mother’s ancestry. Mitochondria is found in the cytoplasm of human cells, and is only passed on from a female parent to their offsprings. Therefore the mutation rate for mtDNA is 450 years or approximately one every 22 generations, and having one family member’s mtDNA information would be usually applicable to the entire family related through a female ancestor. The mtDNA analysis would be able to provide information regarding the geographic area from which the matrilineal family line originated, as well as any other traits that might be passed on through them.

3. Y-DNA offers information passed through male predecessors, as it is in the Y-chromosome that makes an offspring born as a male. Similar to mtDNA, Y-DNA also has a slow mutation rate of about 150 – 200 years. Information about the origins of the patrilineal line can be found with a test for Y-DNA.

A genetic test will provide your results about your genetic makeup. Only males are able to do a Y-DNA test, as women lack the Y-chromosome, whereas, a mtDNA test can be done by anyone. You can find the degree of familial ties with another individual by comparing your DNA sequence to theirs. As more individuals do these genetic tests, the companies’ population database becomes more and more robust. So, eventually you might be able to get more specific information about the region of your ancestral origin.

Different companies offer different versions of the Y-DNA and mtDNA tests, which means that some tests use more genetic markers than the other, giving you a more comprehensive information about your family’s lineage. If you’re trying to find out details about individuals with your particular surname, you’ll need to get a test that looks at more in-depth markers than a general ancestry test. You may find some companies offering package deals in which you can order both a Y-DNA and mtDNA test.

How to Get a DNA Test?

Commercial tests are available for each DNA type. At the moment, five companies offer commercial DNA testing: FamilyTreeDNA, Ancestry.com, 23andMe.com, Nat Geo and DNA Tribes. All of the companies offer some type of ethnicity report, but only 23andMe will give a chromosomal view, showing physical traits and medical predispositions.

The first thing you should do is research the company. Make sure the company has a good reputation. Each company relies on its own proprietary database of DNA information. The larger the database is, the more accurate your results will be. And a respected company is more likely to stick around long after you take your test. Some companies will even send you updated information about your results as they refine their databases.

Getting a test is as simple as ordering the right test kit from the company you have chosen.The company will ship the test to you. The test kits are simple and painless. It usually consists of swabbing the inside of the cheek for DNA samples or filling a tube with saliva samples. The kits are then sent directly to a lab where the DNA is extracted, amplified, and analyzed. The DNA sequences are then compared to and matched with samples from a reference database of haplotypes – a set of closely linked genes or DNA polymorphisms – that have been identified in specific populations. If a person’s DNA sequences match certain sequences in the database, the information can be used to determine the populations with which that person shares maternal or paternal ancestry.

Once the company completes the analysis of your DNA, it will send you the results. It is as simple as that. Some testing companies create profile pages for customers on their Web sites which is like a social networking site. This can help you get in touch with other customers of that company who have similar DNA results to your own.

Some companies will give you the option to add your de-identified results into their open database. Your results will help the company refine its classifications, as each customer’s data adds to the bigger picture. If other customers have genetic results that match yours, the company may contact you and the other people to let them know of the match. By getting in touch with people who match your results, you may be able to fill in the gaps in your family’s history. You may also discover distant cousins who have been separated as the family size increased or migrated.

There are also websites where you can create an account and post your results. One may wish to search their surname – many surnames have Web sites dedicated for genealogical research. Or they can post the results to their own personal site.Or they can even post the haplogroup they belong to, but haplogroups are very general, they just define genetic populations. A genetic population isn’t necessarily linked to a particular ethnicity, culture or even geography. And the classifications for haplogroups for Y-DNA results are different than those for mtDNA results.

DNA Genealogy Projects

There are plenty of ongoing genealogy projects which attempts to trace familial history that range from regional to global scale. Some projects were created to to trace an overview of human migratory patterns over time, these are more anthropological than genealogical in nature. Others help people get in touch with fellow genealogists to solve mysteries and connect to family members who may be separated by geography and generations alike.

One of the largest projects is The Genographic Project spearheaded by National Geographic. You can participate in the Genographic Project by purchasing a test, which costs around $100 and submitting your sample to the project. This project does not help you find out who your great-great-grandfather was. But instead, the project’s main aim is to map the migratory patterns of human history. It’s about as big of a picture as you can get.

The USGenWeb Project is a volunteer organization dedicated to helping citizens of the United States research their family backgrounds. The project has links to each state project. Within the state project site, you’ll find links to resources that might help you find out more about your family. In many cases, the links will tell you where you need to go to see official documents that have your family’s information on them. You’ll still need to do some legwork to fill in the gaps, but the projects resources can give you a good place to start.

The WorldGenWeb Project has similar goals but on a global scale. It contains links to regional genealogical project Web sites. Volunteers can elect to oversee a particular region. It becomes that volunteer’s duty to gather research resources and create forums for members to connect with one another and discuss family histories.

Many surnames have their own DNA projects. Most of these projects began as personal projects that grew over time and merged with other projects for the same surname.

Keep in mind that these projects are meant to help you in your search for information about your family. They do not present your complete family history through a single search query. You’ll most likely need to do additional research and contact distant relatives to build out a full history. If you haven’t used DNA to explore your genealogy, you should. It is a wonderful replacement to the traditional research methods you are using. Even better, it has the potential to unlock genealogical mysteries when the paper trail ends. Use it, and discover your true roots.