Nacho Esteban of 24Genetics told us, “Ancestry is not an exact science. The top five companies in the world would show very similar results when talking about continents; the similarity is smaller when talking about countries. In regional ancestry, some border regions are difficult to identify and sometimes there may be discrepancies. So we cannot take the information as something 100% sure. But at the end, it gives a great picture of where our ancestors were from.”
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.
Genes make up the blueprint for our bodies, governing factors such as growth, development and functioning. Almost every cell in the human body contains a copy of the blueprint, stored inside a special sac called the nucleus. The estimated 23,000 genes are beaded along tightly bundled strands of a chemical substance called deoxyribonucleic acid (DNA). These strands are known as chromosomes. Humans have 46 paired chromosomes (half inherited from each parent), with two sex chromosomes that decide gender and 44 chromosomes that dictate other factors. Certain portions of DNA are unique to each individual. DNA profiling is a way of establishing identity and is used in a variety of ways, such as finding out whether twins are fraternal or identical. DNA samples are usually obtained from blood.
There may be a couple of reasons why your son's ancestry results did not show Italian heritage. Firstly, your own result was "72% Italy/Greece", and so it is not certain how much of this percentage was Greek or Italian. The fact that your son's DNA results estimated him to be "30.5% Greek" could suggest that your "Italy/Greece" percentage was actually indicative of majority Greek heritage, and not Italian. Your son would then have inherited roughly half your Greek DNA.
When STR profiling is carried out, the whole of the person’s DNA is not examined. Rather, specific regions (loci) of the DNA which are known to vary greatly between individuals are examined. These loci are areas of the DNA which contain varying numbers of repeating sequences known as short tandem repeats (STRs). It is the number of these repeating units which can differ between individuals. If there are differences between profiles obtained from different samples, the two samples cannot have come from the same person. If, however, the profiles match, then it follows that the samples could have originated from the same person or from any other person who happened to have the same STR profile.Â
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.
Companies differ in terms of which reference populations they use. Some companies will create their own reference populations, while others will use populations identified in published studies. For example, 23andMe produce their own reference populations by sampling their customers (as long as the grandparents of those customers were all born in the same country). They then combine this data with public population data, produced by projects such as the Human Genome Diversity Project.
In my research into my Cruwys ancestors in Devon, I hit a brick wall trying to find William George Cruwys (born 1821), the brother of my great great grandfather, Thomas Cruwys (born 1831). William disappeared from English records after the 1841 census. I found a William of the right age in Prince Edward Island, Canada, but couldn’t find any records to confirm a link, though naming patterns provided a strong clue.
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.
It should be said that if these Family Finder tools sound like a good way to add to your family tree, the majority of the matches you’ll be shown will be 3rd cousins or more distant, and it can take a significant amount of research to place them on your tree. That said, if you’re prepared to contact your matches and try to piece together your familial connection, using the Family Finder feature can be lots of fun and a great way to make friends all over the world!
Then comes the section about serious genetic variants. So far as “counselling” goes, previously, I’d waved away concern for my psychological welfare from the Observer’s science editor (“I’m a former goth,” I said. “My default setting is ‘doomed’”), but it turns out to be quite daunting. It doesn’t help that I initially mistake the full list of potential conditions for my own results, hence (thankfully briefly) thinking that I have higher risk factors for everything going. It makes me wonder – how many other people are going to do that?
Y-DNA Tests: Y-DNA testing examines the Y chromosome passed only from father to son and can therefore be used to gain a better understanding of your paternal line. This can be a very interesting study for those focused on surname research, especially since the Y chromosome can give information about deep and recent roots. Because only men carry this chromosome women will need to test their father, brother or other male relation to use this test for genealogy purposes. Again, FTDNA is the leader in this type of testing and has a wealth of information, groups and forums to help.