Once your genetic information is out there, it’s difficult to undo. Also, once you know something about yourself, it’s impossible to forget. Revelations such as having different parents than you expected or finding unknown half-siblings are difficult to process at any age, but it’s particularly troubling for kids. However, you can always simply opt out of family matching features.
Most of this trait data tells you things you already know, like your hair and eye color, but it is fun to see them compared to your genetic relatives and the world at large. We also found it fascinating to learn more about how these physical traits are genetically determined. For example, finger length ratio is determined by hormonal exposure in the womb, with higher testosterone exposure resulting in a better chance of having a longer ring finger. 23andMe’s Health report for finger length ratio looks at 15 gene markers to estimate your likelihood of having longer ring fingers or index fingers.
Admixture percentages are one of the biggest reasons people choose to have their DNA tested. This report attempts to accurately match your DNA with population samples from around the world to tell you where your ancestors came from. Each of these companies has strengths and weaknesses when it comes to this calculation, and in the reports it provides to users.
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. 
On all platforms except for National Geographic, you can initiate a search for relatives, though some services let you upload your National Geographic results for further analysis. The software continually searches for DNA matches as more people share their results. This feature may be useful if you're building a family tree or looking for relatives you've never met; otherwise, it may more of a nuisance. You can opt in or out at any time, and the DNA service doesn't share your contact information. Relatives can message you through the software, though. If you already use genealogy software, you may be able to download your results and upload them into your preferred program. Otherwise, AncestryDNA and others featured here have family tree software that you can easily link.
The components of the STR profile are represented as data consisting of a series of peaks. For each location (locus) along the DNA molecule there will usually be two peaks, one from each parent, representing STR components (alleles) with differing numbers of repeats. If an allele with the same number of repeats is inherited from both parents, only one peak will be present.
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.

I’m afraid that you're unlikely to find a DNA test that can tell you specifically which tribe your ancestors came from. We’d recommend taking a look at the answer to this forum post, which explains a bit more about why this is the case: https://dnatestingchoice.com/forum/showthread.php?1259-Welsh-Ancestry. Although the original post was about Welsh ancestry, the concepts are the same regardless of where in the world the specific groups of people lived.


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.
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.
DNA profiling isn’t exclusive to human DNA. Animals also have genetic markers in their DNA which can be used to build up a profile for DNA identification or determining parentage. The most common animals that this is used for are dogs. Similarly to human DNA profiling, dog DNA profiling uses 10-20 markers in order to build up a profile that can be used to identify your dog if it is ever lost or there is some kind of ownership dispute. Companies that offer this service will often include the profile in the form of a certificate, with details about your dog along with its DNA profile. It should also be said that these companies tend to store your dog’s profile in their database, so you that you can check back with them if you ever need to.
When a sample of biological material contains DNA from more than one person, this can result in a “mixed DNA profile”. In such profiles, there may be a reduced amount of useful information regarding whether or not a specific person could have contributed to this sample. This could be because the contributors may share one or more DNA alleles, resulting in the masking of the DNA of one person by that of the other.
FTDNA has the most advanced tools for easily analyzing cousin matches as of now, although it is possible that MyHeritage DNA may catch up. They seem very eager to please customers at this point. FTDNA does fall short when it comes to the ability to sync with developed family trees however. This is certainly not intentional on their part, they have developed some great tools for this purpose, but FTDNA (unlike Ancestry and MyHeritage) does not provide record searches or an online family tree program for the purpose of genealogical research. For this reason they are inherently limited in this regard.
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.
Admixture percentages are one of the biggest reasons people choose to have their DNA tested. This report attempts to accurately match your DNA with population samples from around the world to tell you where your ancestors came from. Each of these companies has strengths and weaknesses when it comes to this calculation, and in the reports it provides to users.
Lets suppose, as we have in the Sinnott/Sennett one name study, we have a whole lot of families who all believe their common ancestor came from Co Wexford, but the paper trail for conventional genealogy research has dwindled away, or we suspect that John and James who emigrated to the US about the same time were brothers but there is no documentation to prove it – genealogical DNA studies can now be used to show whether its possible that two families (that are at the moment quite separate on paper) are actually related and have a common ancestor. And no, we don’t have to go digging up g-g-g-g-grandfather John to get his DNA – remember, he passed it on to his son, and his son’s son, and so on to the present day. So we find a living male descendant and they get their Y-DNA analysed. That gives us a pretty good indication of the genetic signature for the whole family tree (well, the male side, anyway). If we want to check it, we find a distant cousin of the first person who tested and get their DNA analysed. If its a very close match, then bingo – we know the Y-DNA genetic signature (and whats known as a haplogroup) for our whole family group.
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