DNA is found in most cells of the body, including white blood cells, semen, hair roots and body tissue. Traces of DNA can also be detected in body fluids, such as saliva and perspiration because they also contain epithelial cells. Forensic scientists and Police officers collect samples of DNA from crime scenes. DNA can also be collected directly from a person using a mouth swab (which collects inner cheek cells). Find out more in the article Crime scene evidence.


There are many things to think about when deciding whether genetic testing is right for you. Although these tests can provide important information about health risks, they can also be upsetting or raise questions about what the results mean. Genetic tests also have certain limitations that are important to understand. Your personal and family medical history, as well as your goals for testing, should all factor into your decisions about whether and how to test.

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. 


The 23rd pair of chromosomes is comprised of sex chromosomes – X and Y chromosomes that determine whether you’re male (XY) or female (XX). Traits like red-green color blindness, male pattern baldness and hemophilia are specifically linked to X or Y chromosomes and are called sex-linked characteristics. All of those examples, and most other sex-linked traits, are X-linked and more common in males, who only have one X chromosome. Many DNA tests isolate Y DNA in males to show consumers their paternal haplogroup. Since the Y chromosome is directly inherited from father to son, it is possible to trace direct paternal lineage for many generations.
Almost immediately after the technique of DNA profiling was developed, it was put to legal use. The case of Colin Pitchfork, the first criminal convicted using DNA fingerprinting, is well publicised, but the very first use of this technique was actually in an immigration case. Alec Jeffreys (the person who developed the technique) helped a Ghanaian boy to avoid deportation by comparing his DNA to that of his alleged British mother’s, to prove that he was her biological son. Since that case, DNA profiling has been used in thousands of cases of immigration, by either keeping families together or reuniting them by proving biological relationships.
There are a number of reasons why the vast majority of living humans are a blend of ethnicities. Firstly, from around 1850 onwards, people started to migrate around the world and mix in large numbers. Secondly, as national borders have changed over time, the only clear cut ethnic groups are those that are highly isolated. For example, as individuals have migrated in large numbers between France and Britain in the last few thousand years; those in Northern France exhibit a similar ethnic mix to those in Southern England.
The little changes are where “mutations” occur over generations – these aren’t necessarily bad, it just means that the gene has been copied slightly differently as it passed from father to son. Because its possible to predict how often mutations are likely to occur, comparing the Y-DNA from distant male cousins with a common ancestor (and seeing how many differences there are in a standardised set of markers tested) allows a rough estimate of when that common ancestor might have lived. A very close match between two men who share a common surname (only one or two differences) makes it very likely they are related, and a bigger number of differences makes it either less likely they are related, or that the most recent common ancestor is very many generations back.

Newman says that there’s a basic lack of “literacy” and understanding about genetic testing, among the public and even other health professionals. People are given false reassurances or made to panic (just because you have certain genetic variants, it doesn’t mean that you will develop a particular condition). Newman also makes the point that, in his field, counselling happens before and after testing and, while people with cancer or heart issues nearly always opt to have the test (as they can then take action to varying degrees), often people with conditions such as Huntington’s disease in their family decide not to go ahead because a diagnosis would change nothing for them. In any event, Newman says that, with genetic testing, while there are different levels, intensive counselling is always “absolutely key”.
When we speak, co-founder Hamish Grierson describes Thriva as “a lifestyle brand with medical-grade testing at the back end”, an opportunity for “people to see themselves as consumers rather than patients”. Grierson gives examples of people who have benefited from Thriva testing, sometimes picking up early on serious issues. As for alarming people, Grierson says that Thriva has on-site facilities to discuss results and is intended to be “complementary to the NHS” rather than replacing it: “If there are questions we can’t answer, we’re very clear that people should pick it up with their GP.”
Looking at your raw DNA file might not give you any useful information unless you’re looking for a specific marker. You can also upload the file into a third-party DNA databases for information or results beyond what’s available from your testing company. This process is not without risks, as your DNA testing company only ensures the security of your personal information in its own environment. Once you download the file, you’re responsible for the file’s security. However, uploading your raw DNA to a third party database isn’t inherently unsafe — just be cautious.
Three of the companies, MyHeritage, Ancestry and FTDNA, use the Illumina OmniExpress chip and 23andMe uses the new Infinium® Global Screening Array chip from Illumina. The fact that all of the chips come from the same company may be confusing, leading some to believe that all tests are created equal. This is not the case. The chip used to process DNA samples is only one part of the process. Each company develops their own analysis of the results, references different population samples and provides different reports. In addition, each one of these DNA test providers offers different tools for you to analyze the data you receive, creating variations in results, accessibility and usefulness.
This is another feature of these genetic-testing sites – they are littered with caveats and disclaimers, forever emphasising that they’re not actual “diagnostic tests” and, if you are really concerned by your results, to seek further advice from your GP or another health professional. As has been pointed out by McCartney, when anything looks serious, ultimately it’s back to the very GP and exact NHS infrastructure that these kits profess to smoothly bypass.
So what are you waiting for? If your family’s genetic signature hasn’t yet been tested, how about considering contributing to the genealogical record and resource for your family by finding one or two men to take a Y-DNA test. If you are a male S-NN-T descendant then please check out the Sinnott/Sennett (and variants) surname project at familytreeDNA.com – you even get a discounted rate for the Y-DNA37 test if ordered through the project. http://www.familytreedna.com/group-join.aspx?Group=Sennett
For better ancestry and medical insights, you should encourage family members, especially parents and grandparents, to take a DNA test as well. If your family is from a specific geographical location for generations, your samples could potentially improve the service's reference panel, in turn improving results for everyone. If you’re female and take a test from 23andMe or LivingDNA, you can view paternal haplogroup information, and you get more information when one of your male family members takes a test as well.
What we would expect to find then in this example is that the two descendants of John show a very close match, and the two descendants of James also show a very close match (because we know from conventional paper based research that they are related). If all four match very closely, then that’s further evidence to add to our theory that John and James were really brothers. Not conclusive proof- but pretty solid evidence.

To prepare to take a cheek swab sample, you also have to refrain from eating for about an hour before. Swab kits generally contain more components, including one or two swabs and containers to protect the used swabs from contamination. We found it easiest to organize all the pieces first, to prevent any fumbling with a sample collection swab in hand. Some cheek cell kits put a stabilizing liquid in the sample containers, which required extra caution to prevent spilling.
Health and disease info: DNA testing can also indicate which conditions for which you may have a preponderance. It's a controversial feature, to be sure. Knowing that you have a genetic predisposition to a certain form of cancer may make you more vigilant for testing, but it may also lead to increased stress -- worrying about a potential condition that may never develop, even if you're "genetically susceptible" to it. The possibility of false positives and false negatives abound -- any such information should be discussed with your doctor before you act upon it.
As my dad and I have begun to explore our genealogy over the past seven years or so, we’ve found that our family is largely from Spain, which is no big surprise. Colombians have a wide range of ethnicities, which explains why many Colombians, including my mother, have white or fair skin with blue eyes. My dad also suspects we have German ancestry somewhere back there.

DNA tests offer a wealth of insights into your connections to family, history and geographical locations. They both entertain and encourage you to dig into what you know about yourself. The tests make great gifts to bring you closer to your family and involve you and your family in the development of a cutting-edge science at the same time. Beyond that, the information is extremely useful for adoptees, people looking for lost relatives, genealogists and for medical science. 
The DNA holds or stores the information using code in various forms, configurations, instructing cells what to do. Yes the DNA sends out instructions, ( or "tells" other celss what to do etc.. like a computer program can tell a robot what to do or carry out multiple functions. My question still remaining is... information came from an intelligent mind... not the physical data that it holds like DNA holds the information, it can copy the information.. but DNA did not code itself...it received the instructions.. no matter how long ago from a mind or an intelligent designer. Does ANYONE on this site agree? I have not seen anyone else question this.
Guidelines recommend that women with a BRCA1 or BRCA2 variant should be screened for breast cancer earlier and more often. Risk-reducing surgery or medication may also be offered. Men with a variant should be screened for breast cancer. Screening guidelines for prostate cancer vary. This test is not a substitute for visits to a healthcare professional for recommended screenings. Results should be confirmed in a clinical setting before taking any medical action. It is important to talk with a healthcare professional before taking any medical action.

If you opt in to 23andMe’s family matching feature, you can connect with other 23andMe users with similar genes. This feature lets you view your matched relative’s display name, sex, profile photo, percent of DNA shared, number of DNA segments shared, relatives in common and haplogroups. The interface also estimates how closely you are related to each match. It’s very easy to connect with your matches on the website, and you can request more information by inviting them to share DNA reports.
23andMe is a bit different in that many people have tested with their company for the health results and are not necessarily interested in genealogy or matching with relatives, even if they opted into this feature. That doesn’t mean you won’t get a good response when reaching out, but it may be less common than with the other testing companies. Recently 23andMe has been placing more focus on genealogical testing, however, so this is may be shifting.
AncestryDNA, 23andMe, HomeDNA, Living DNA, and MyHeritage DNA all provide reports of your ethnicity, some showing maps of where your ancestors lived along with information about the particular countries and regions. National Geographic goes further back, pinpointing where in Africa your ancestors came from and tracing migration patterns through to near-present times. It's less about your personal genetic makeup and more about who your ancestors were and how you're connected to the beginning of civilization.
As discussed, DNA is much more resilient than the items traditionally used to determine someone’s identity, such as passports, licenses or dog tags. In addition, a tiny DNA sample is often enough to produce a complete DNA profile, whereas paper or digital records can become difficult to interpret with even small amounts of damage. DNA profiling for DNA identification therefore offers a quicker and more conclusive method of identification than other approaches.

Whether it’s an autosomal test, a Y-DNA test or an mtDNA test, virtually all providers use the same science. Some providers offer an ‘off the peg’ solution such as Ancestral Origins™ or AncestrybyDNA™, so if you’re interested in these you should shop around for the lowest price. Most providers offer a test that interprets and presents the results in a unique way, so if one of these catches your eye, look for examples of how the results are presented on their website before you buy.
You control your account privacy. Findmypast and Living DNA keep your data private unless you choose to share information, such as your family tree or DNA results. Your data is encrypted and stored on secure servers, only accessible by staff, vital service providers (such as our laboratory partners) and you. Living DNA has carefully chosen a European laboratory to conduct its DNA testing. Findmypast and Living DNA only disclose your data to third parties where we have appropriate agreements in place. For example, trusted third-party payment processing companies. Findmypast and Living DNA are ISO accredited for data and information security.
There is currently no known cure. People with AAT deficiency are encouraged to avoid smoking and consider getting certain vaccinations. For those with symptoms, treatment focuses on management of lung and liver problems. Direct replacement of the AAT protein into the blood may be used to slow the progression of lung disease. Lung and liver transplants may be beneficial in some cases.
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.”
AncestryDNA, 23andMe, HomeDNA, Living DNA, and MyHeritage DNA all provide reports of your ethnicity, some showing maps of where your ancestors lived along with information about the particular countries and regions. National Geographic goes further back, pinpointing where in Africa your ancestors came from and tracing migration patterns through to near-present times. It's less about your personal genetic makeup and more about who your ancestors were and how you're connected to the beginning of civilization.

I had two tests . One FamilytreeDNA said I was Notrhwestern European – mostly British Isles on the mothers side but then 45% Non-northern Euro. – Greek and Turkish, etc. But 23 and me said nearly all Northern European with 1% Askanazi. Huh/ Same sipt in the old jar. Somebody’s wrong! Since I know nothing about my father’s side the autosomal test was all I had for any clues at all. Kind of worthless at this point.

When asked about how database size affects ancestry results, David Nicholson, co-founder of Living DNA, told us, “The tests absolutely rely on the reference database. If you have Polish ancestry but there are no people in the database who are Polish, then what the test will do is show what the next closest group is next to Polish, like German or Eastern European ancestry.” 
Another key customer type could be people like myself, hurtling through middle age, perhaps just starting to feel the cold bony hand of mortality clamp down on their shoulder. People, who, in the past, may not have exactly prioritised their health, who are starting to wonder what may be in store for them and who are in the (“Hypochondriacs R Us”) market for some hard-core insight and advice.
Otherwise, the home-testing kits could be said to fit in with our increasingly health-conscious and, if you wish to be cynical, narcissistic times. What says you’re “special” more than finding out everything about yourself, right down to the nitty-gritty of genetics? In this way, these kits could be viewed as the latest plaything of the “worried well”. You could see how the scientific approach would appeal to the health-obsessed of all sexes and ages, your marathon runners and serious gym-goers, who take their fitness extremely seriously.
Another key customer type could be people like myself, hurtling through middle age, perhaps just starting to feel the cold bony hand of mortality clamp down on their shoulder. People, who, in the past, may not have exactly prioritised their health, who are starting to wonder what may be in store for them and who are in the (“Hypochondriacs R Us”) market for some hard-core insight and advice.
Our Ancestry Service helps you understand who you are, where your DNA comes from and your family story. We analyse, compile and distill your DNA information into reports on your Ancestry Composition, Ancestry Detail Reports, Maternal & Paternal Haplogroups, Neanderthal Ancestry, Your DNA Family and provide a DNA Relatives tool to enable you to connect with relatives who share similar DNA.
Most direct-to-consumer DNA test companies warn that the tests may reveal things you wish you didn’t know about your family. For example, you could find out that one of the people who raised you isn’t your biological parent or that there’s an entire branch of your family you didn’t know about. There isn’t a way to prepare for a shock like that, but you can opt out of a company’s family-matching services if you’d rather not know.
The little changes are where “mutations” occur over generations – these aren’t necessarily bad, it just means that the gene has been copied slightly differently as it passed from father to son. Because its possible to predict how often mutations are likely to occur, comparing the Y-DNA from distant male cousins with a common ancestor (and seeing how many differences there are in a standardised set of markers tested) allows a rough estimate of when that common ancestor might have lived. A very close match between two men who share a common surname (only one or two differences) makes it very likely they are related, and a bigger number of differences makes it either less likely they are related, or that the most recent common ancestor is very many generations back.
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