It could be that, in the main, genetic-testing kits such as these could, if promoted and used responsibly, end up zoned completely away from legitimate science and medicine and placed where perhaps they belong, firmly in the lifestyle-extra zone, if and when people think they’re “worth it”. Though, somewhat tellingly, when I ask Newman if he thinks that any of the genetic testing kits are worth buying, he instantly says: “No. I’d say, go to the cinema, watch some sport. Spend the money on something nice, something life-enhancing.”

Ethnicity can be defined in many ways and by a wide range of factors. Culture, language, nationality and religion are just a few of the influences that can contribute to your sense of ethnic identity. DNA testing offers another way to help you define your ethnicity, by looking at your genetic ancestry. Even families that have lived in the same place for several generations may have a diverse genetic heritage, and if you were to trace your ancestry back several hundred thousand years, the current thinking is that you’d discover you share the same ancestral origins as all humans, in Sub-Saharan Africa.
Most companies will use algorithms to compare the genetic variants uniquely associated to a reference population with those identified in the person being tested. This can help them exclude unlikely population groups from your ethnic mix, and ensure that the ethnic groups you’re shown to be composed of are more accurately reported. Although most companies will share the reference populations they use with their customers, they rarely provide information on the algorithms they’ve developed.

My favorite DNA test for finding ethnicity is Ancestry DNA.  My second favorite is 23 and Me.  The way Ancestry presents their DNA results is easy to understand, and their test is general less expensive than 23 and Me.  I have also found Ancestry DNA’s ethnicity estimates very closely represent what I have been able to research the old-fashioned way, both in my family and that of my husband and other family members.
In addition to showing geographic ancestry percentages, some direct-to-consumer DNA tests also include insights about physical traits like hair and eye color. With 23andMe, this trait information is mostly available in the upgraded Ancestry + Health kit, but some interesting tidbits can be found in the Your DNA Family report, which is available if you opt to participate in the DNA Relatives service. 
Molly K. McLaughlin is a New York-based writer and editor with more than a decade of experience covering technology. She has tested and reviewed all sorts of software, mobile apps, and gadgets. Before launching her freelance business, she was an editor at PC Magazine, covering consumer electronics, followed by a stint at, a revie... See Full Bio
MyHeritage shows cousin matches as part of your DNA purchase for free and has some really wonderful tools to connect your research to your DNA matches. Using smart matching features to see how your tree is connected to others, and adding records you discover this way, may cost an additional monthly fee however. Still, MyHeritage is generally less expensive than Ancestry. You can also try their record collections for free here.
If you’re more interested in learning about the relatives you already know you have, 23andMe has a few unique tools that let you compare your DNA with your children, parents and grandparents. If multiple people in your family tree want to get tested, fill out a GrandTree, which shows you which segments of DNA you inherit from each of your tested parents or grandparents. While nowhere near as comprehensive as AncestryDNA’s family tree and genealogy tools, 23andMe’s more nuclear approach to family genetics is a great option that lets you explore your genetic relationship with more immediate relations.
DNA fingerprinting is commonly used to compare DNA samples taken from the crime scene with those taken from suspects, to either prove or disprove their innocence. In the UK, 10 markers are analysed to produce DNA profiles from the samples taken in criminal investigations. These are then compared to (and stored in) the National DNA Database (NDNAD) to identify if there’s a match. This database currently contains DNA profiles for 10% of the UK population, along with the individuals’ names and ethnicities. Anyone who’s been arrested for a recordable offence has their information recorded on the database, unless they are found innocent or not charged – in these cases, the individuals’ biological samples and corresponding information is destroyed within six months of sample collection.

Even though we are all unique, most of our DNA is actually identical to other people’s DNA. However, specific regions vary highly between people. These regions are called polymorphic. Differences in these variable regions between people are known as polymorphisms. Each of us inherits a unique combination of polymorphisms from our parents. DNA polymorphisms can be analysed to give a DNA profile.

More controversially, some of these kits profess to tell you your biological (as opposed to actual age) by measuring the length of your telomeres (in basic terms, the caps at the end of each strand of DNA that protect chromosomes, like plastic tips at the end of shoelaces). Other tests, such as 23andMe, predict higher risks of developing serious conditions, such as multiple sclerosis, Alzheimer’s and Parkinson’s, including the test for BRCA1/BRCA2 (breast and ovarian cancer) that Angelina Jolie famously underwent, going on to have a preventative double mastectomy and surgery to remove her ovaries.
In the case of a great-grandchild, or a great-great-grandchild, something even stranger can happen.  Remember that a child will get half of their mother’s DNA, but there is never ever guarantee which 50%.  The way it is chosen is fairly random, as far as scientists know.  Take the example of the 100% Eastern European person.  Their great-grandchild will inherit 50% of their DNA from their part-Eastern European parent, but there is a good chance that they won’t inherit all of the Eastern European DNA that they could potentially inherit.  It’s possible for a person to share NO DNA with a great-great grandparent, even though there is a verified genealogical relationship.
AncestryDNA is appealing to many because the results can be matched (to some degree) with many well-established family trees, but major privacy concerns (about how your data is used and sold) have been present in the past. For many, this is a deal breaker. They also offer the fewest advanced tools for analyzing data, although their database is very large.
One of the most popular reasons for doing a DNA test is to determine ethnicity.  Many people start out on their DNA journey trying to learn about their ethnicity and end up discovering new family members, or learning something really cool about their family history.  Is there such a thing as a DNA test for ethnicity, and if so, which one is the best?
If you have the Health + Ancestry Service you have access to the full 23andMe experience. If you only have the Ancestry Service, you can easily upgrade to the Health + Ancestry Service for £90 which gives you access to all 125+ reports on ancestry, traits and health. You are eligible to upgrade once you have received your Ancestry reports. To upgrade, log in to your 23andMe account and navigate to the Settings page. You will receive immediate access to your new health reports.
With a 16-day turnaround, MyHeritage DNA was one of the first companies to send back our test results, but I found the contents of my ancestry report to be a bit off, especially when compared to my geographic ancestry reports from other companies. I was born in Korea and therefore expected at least a little of my Korean heritage to make it onto my ancestry map, as it did with other services, but MyHeritage didn’t report any Korean heritage. 

As discussed earlier, in order to determine the ethnicities present in your genetic make-up, genetic ancestry companies can analyse your autosomal DNA to seek out the genetic variants uniquely associated to certain population groups. These groups are known as ‘reference populations’, and they’ve been constructed by sampling the DNA of modern populations around the world, as well as from human remains at various archaeological sites. By identifying these genetic variants in your genetic code, companies can report on the groups that have contributed to your DNA.

In our tests, we did find consistency across our results on the continental level. For example, my ancestry is exclusively East Asian, but 23andMe breaks it down into 80 percent Korean, 10.5 percent Japanese and 0.8 percent Chinese, with the remaining 8.7 percent in broader categories. However, Ancestry reports my DNA as 98 percent Korean and Northern Chinese, with only 2 percent Japanese. National Geographic places 85 percent of my ancestry from Northeastern Asia and 14 percent from the South China Sea region, with my DNA most closely matching the Korean and Japanese reference populations.
mtDNA Tests: These type of tests look at the DNA found in our cell’s mitochondria. Mitochondria is located in the cytoplasm of the cell (surrounding and separate from the nucleus where most DNA is found) and is therefore only inherited from your mother. This means that a mtDNA test can help you understand the ancestry of your maternal line only. The nature of this test option also limits it to the understanding of deep ancestry (not so helpful for genealogists)–although the more detailed the test, the more accurate and specific your results become. The most commonly used tests for this purpose can be found through Family Tree DNA (FTDNA) and they have a huge amount of helpful information on better understanding the science and genealogical significance of this method of genetic testing.