Home DNA testing has gone from a niche pursuit to a simple way to map out your family tree. A DNA test can be used to determine paternity and research ancestry or familial origin. And over the past few years, they've become quite affordable, with a wide range of companies selling DNA test kits -- from trailblazers such as Ancestry and 23andMe to upstarts that include LivingDNA.
I was interested in the ethnicity test provided by African Ancestry because of their claim to be able to place your ancestry in a current African country or region. However after reading multiple reviews, I'm hesitant to spend $300 to find out my ancestors are "West African" or from Sub Sahara Africa. Is there any company whose test can place Ancestry within a specific region of African?
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.
Since genome sequencing is still a relatively young science, we don't recommend submitting your child’s DNA to direct-to-consumer companies. We do encourage consulting with your doctor about genetic testing for your child. Due to some concerns with the DNA testing industry, the choice to have one’s genes sequenced by a private company should be made with informed consent. Those concerns are magnified when applied to children, who cannot make their own decisions regarding the unlikely potential risks or privacy concerns.
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.
There is one really, really important thing to know about this estimate, however. Each child inherits 50% of their DNA from each parent. That means that 50% of their parents’ DNA does NOT get passed down to the child. This can mean that a child of a 100% Eastern European person will only show 50% Eastern European DNA, and their grandchild will only show 25%, and their great-grandchild 12.5% – in a perfect scenario.
The SGM Plus system of DNA analysis targets ten loci, each of which contains two alleles. These are the “short tandem repeats” that vary between individuals. In addition, a further locus is targeted that acts as in indicator of the sex of the donor. A “full” DNA profile is one in which all of these loci have produced a reliable and reportable result. Occasionally, the processes used to target some of these loci fail, resulting in an incomplete or “partial” DNA profile. The most common reasons for such failure are either that a very small amount of DNA was present in the sample, the DNA may have become degraded, or that substances may have been present in the sample that may have inhibited the analysis process. Depending on the degree of success of the DNA analysis, the match probability calculated from a partial DNA profile may be reduced below the 1 in 1 billion that would be obtained from a full profile.
The only patients having their genome sequenced are those with certain cancers or rare diseases. In some cases, family members may also be asked to participate. To take part, a patient must first be referred by a consultant, before being taken through an extensive consent process to ensure they know what participation in the project means. As well as the genome sequence, Genomics England asks for access to a patient’s lifetime medical records so that links can be made between their genetics and their individual disease. The NHS has made it very clear that, for many participants, taking part in this project won’t help them treat their disease. But it is hoped that the information they provide will go on to help treat others in the future.
While DNA contains material common to all humans, some portions are unique to each individual. These portions, or regions, contain two genetic types (alleles) that are inherited from the person’s mother and father. A person’s DNA profile is made by investigating a number of these regions. In a paternity test, for example, the mother’s DNA profile is compared with the child’s to find which half was passed on by the mother. The other half of the child’s DNA is then compared with the alleged father’s DNA profile. If they don’t match, the ‘father’ is excluded, which means he isn’t the father of that child. If the DNA profiles match, the ‘father’ is not excluded - which means there is a high probability (more than 99 per cent) that he is the father. DNA tests such as this can’t offer 100 per cent proof.
A few of the DNA tests we tested, including the National Geographic Geno 2.0, use genetic sequencing instead of genotyping. Sequencing is newer in the mainstream direct-to-consumer DNA testing market, as it used to cost more and take much longer to sequence a person’s DNA. Sequencing identifies the exact makeup of a certain piece of DNA – be it a short segment or the whole genome. The Helix tests sequence the Exome, which are the parts of the genome responsible for protein production, plus several other regions of interest.
Testers appreciated the amount of information and context given with each report. For example, the regional ancestry report matches your DNA to broad world regions on a map, but it also compares your DNA to two more-specific reference populations. My regions were Northeastern Asia and South China Sea, which fit the Korean and Japanese reference populations. Another tester was matched to 11 geographic regions throughout Europe, North America and West Asia, and they were matched to Argentinian and Puerto Rican reference populations.
The first kit I try is Thriva’s baseline test (£49), which, like all its products, checks your blood. The box arrives promptly enough (containing spring-loaded needles, a little collection tube, antiseptic wipes, plasters, etc), but there’s a problem. The idea is to prick your finger and massage blood into the tube, but I just end up making my fingers sore and what I get out barely smears the top of the phial. Maybe it’s just me, but it turns into a right faff. In the end, I take advantage of Thriva’s service to send someone out to take a sample of blood from my arm.
The 100,000 Genomes Project is an NHS initiative, run by Genomics England, and is the largest national genome sequencing project in the world. On entering, patients have their entire genome, of more than 3bn base pairs, sequenced. This is different from commercially available genetic testing kits, such as those from 23andMe, which only look at very small stretches of DNA in a process called genotyping. The hope of the NHS is that having so much genetic information, from so many different people, will allow “groundbreaking discoveries about how diseases work, who could be susceptible to them, how we can treat them, and what treatments might work”.
Men have an X and a Y (chromosome) that are paired together. Women don’t have the Y, they just have two X’s. A child’s genes come from a mix up and recombining of the two parents. So a girl child will still end up with two X’s but some bits of them will come from the father’s X and some from the mother’s. A boy child on the other hand may have some bits of X from both mother and father, but his Y will have just come purely from his father – virtually unchanged. That makes Y-DNA such an exciting possibility for genealogy where you want to follow the paternal (surname) line. You could expect that Y-DNA will therefore pass virtually unchanged from father to son through the generations, meaning that the Y-DNA of a man’s g-g-g-g-grandfather will look very much like that of his own Y-DNA – with some little changes.