Most companies will use algorithms to compare the genetic variants uniquely associated to a reference population with those identified in the person being tested. This can help them exclude unlikely population groups from your ethnic mix, and ensure that the ethnic groups you’re shown to be composed of are more accurately reported. Although most companies will share the reference populations they use with their customers, they rarely provide information on the algorithms they’ve developed.
Specific tests for your father’s family include ‘Y-DNA’ tests which focus on the ‘Y chromosomes’ in your cells’ nuclei, passed down from father to son. Specific tests for your mother’s family include ‘mtDNA’ tests which report on a subset of DNA found in the ‘mitochondria’ (your cells’ energy factories), passed down from mother to son or to daughter.
I hope this helps to clear things up. Ancestry DNA testing is not an exact science, and is limited by the fact that we don't inherit the exact same DNA our parents had, meaning that with each new generation, old DNA is lost. Ancestry tests can provide estimations of our genetic ancestry, and though they are improving all the time, they can't tell the whole story of our heritage.
Some concerns about the ultimate efficacy of certain home tests seem to emanate from the industry itself. I did a telomere-measuring test (a mouth swab) by Titanovo, based in north Colorado, which came back saying that my telomeres were too short, putting me at 10 biological years older than I am. However, when I contacted Titanovo, it explained that it had stopped telomere measuring and was now concentrating exclusively on its DNA-utilising “bioinformatics” health, fitness and wellbeing website (analysing client data from other genetic testing sites).
Some of our reports are about serious diseases that may not have an effective treatment or cure. Some people may be upset by learning about personal risks, and risks for family members who share DNA. 23andMe will not share your personal information with an insurance company without your explicit consent. Learn more about third party information sharing here.
Most ancestry DNA kits cost about $100. AncestryDNA, 23andMe’s Ancestry test and National Geographic’s Geno 2.0 test all fall nicely into that price point. If you’re looking for a bargain, we recommend waiting to buy until your preferred test is on sale, as they’re often available well below their usual price. To get the most for your money, buy an Ancestry or 23andMe kit on sale then upload your raw data to MyHeritage DNA’s database, which is free.
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.
— Once you have chosen a test and received your autosomal results there is still a great deal more fun to be had. Independent tools and websites created by scientists and enthusiasts allow you to take the raw data provided from FTDNA, 23andMe and Ancestry DNA and explore them in astounding detail–giving you a wide variety of new admixtures, phasing options, chromosome browsers, SNP tools and connections with family across the world. Gedmatch is our favorite because they have so many wonderful and meticulously updated tools from a variety of sources. Easily upload your raw data and run your results for free (if you love the tools, don’t forget to donate and uncover even more options.)