First of all, what is DNA? The letters stand for Deoxyribonucleic acid, a molecule encoding the genetic instructions used in the development and functioning of all known living organisms. Its structure was first described by Nobel Prize winners Crick and Watson in 1953. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.
I took the AncestryDNA test in 2016 and was disappointed by my initial report, which put my results into a giant area encompassing at least 15 countries labeled “Asia East.” Since then, Ancestry has updated its algorithm and reference population to make its results more specific, but it still only supports 17 regions in Asia and West Asia compared to 296 regions in Europe.
Many DNA databases, including Ancestry, 23andMe and MyHeritage DNA, have family search features, which match your DNA with that of potential relatives. These features help users searching for family, including adoptees and children conceived through sperm donations. Almost every DNA testing service we interviewed for this article had a story ready about how its service facilitated a heartwarming family reunion. Like these from Ancestry, this one from MyHeritage and this one from 23andMe. Because many DNA services also have resources like family tree builders, the tests work in tandem with genealogical research.
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.
Is this a perfect method? No, but it’s a good way to get a general idea about where your ancestors were from. Genealogical DNA tests can tell you a lot about your ancestry going back 300-500 years in time, for the most part. They can also tell you a little bit about your ancestry going even further back. This is why comparing your DNA to those whose families have stayed in a particular area for a long time is a fairly accurate way to perform the estimate.
DNA profiling can also be useful for those who suspect there may be inheritance disputes over their estate once they have passed away. It provides a record that can be referred to long after someone’s death, even when all physical traces of DNA have gone. Therefore, if there is an unexpected claim for inheritance from an alleged relative, your DNA profile can be compared to that of the claimant to prove or disprove a biological relationship and the inheritance rights.
For the uninformed, this is the best discussion on the subject of DNA that I have ever seen. I have been trying to determine who my great great grandfather is for years. I’ve tested with Ancestry and Family Tree DNA, hired ProGenealogists with Ancestry (twice), and still can’t determine who he is. I truly don’t know where to go now. The genealogist that consults with Finding your Roots works for a company that doesn’t do individual research. Who else does the genetic genealogist research that they do?
After collecting spit and cheek cells, we mailed all of the tests at the same time and waited for results, noting all communications from the company in the meantime and how long it took each service to notify us that results were ready to view. We collected data based on testers’ impressions of their results, each service’s features and extras, how easy it was to use and navigate the service’s website, along with several other factors. We added this testing data to rigorous research and information gleaned from conversations with representatives from Ancestry, 23andMe, MyHeritageDNA, LivingDNA, Humancode (now owned by Helix) and 24genetics.
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.
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.
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.
McCartney says that anxious people often contact her, saying they wished they hadn’t done the tests. “These companies often say that it’s worth it for the helpful advice. But I can give you really good advice right now without seeing a single test result: be active, have lots of social networks, do work you enjoy, try not to smoke or drink too much, don’t be overweight or underweight, eat lots of fresh fruit and vegetables. Nobody needs to get tests done to get that kind of basic lifestyle advice.”
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
Each DNA processing company divides the world into regions. One company has divided the world into 24 regions while another company has divided the same world into over 350 regions. This is why there is a noted disparity in the results that people are getting who have happened to use more than one company. results you have received are not necessarily wrong, just perhaps are not as finely sorted as you were maybe expecting.
Some DNA analysis uses the Low Copy Number(LCN) method. This is a modification of the more commonly used SGM Plus method of analysis. The advantage of LCN analysis over standard SGM Plus is its extreme sensitivity; however this is also a disadvantage. The effects of cross contamination are more prevalent in LCN analysis, and due to various effects observed when amplifying very small amounts of DNA any LCN profile should be interpreted with caution.
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.
1. Family Tree DNA’s Family Finder: One of the first to offer these types of tests, FTDNA is generally considered the leader in autosomal DNA testing for ancestry and provides some of the best tools available for genealogists. Their population finder section is currently a bit less specific than the other companies, but FTDNA Family Finder users are eagerly awaiting a much improved update to be released sometime in the next month. Find out about Family Finder here.