DNA testing. Whats best?

+10 votes
I am looking at the different sites for DNA tests and what is the best one to start with?
WikiTree profile: Tiffany Knight
in Genealogy Help by Tiffany Knight G2G4 (4.6k points)
retagged by Ellen Smith
Maybe this is a question more than a comment.

I was told that the DNA we take can be used in a court of law for us, our relations today and in the future.

We think of it as going backwards with our tree but are there really legal repercussions available by having your DNA on record? Maybe I am honest and live in peace but I don't know what the future holds.
That is the question that lingers in the back of my mind. We are uncertain of the future, and probably one of the reasons no one that I know of has taken DNA tests throughout both maternal and paternal. Thank you.

Hi, Sandy and Tiffany.  smiley

I don't know whether it will set your minds at ease or not, but the fact is that none of our common direct-to-consumer DNA tests can be used in any court of law I'm familiar with, certainly not in the United States or the United Kingdom. And it's highly unlikely they ever will be admissible for any legal purpose.

All forensics testing right now examines what are called short tandem repeats (STRs). Each STR consists of an identical set of, generally, 2 to 7 alleles--the DNA "letters" A, C, G and T--that repeat in exactly the same, known pattern multiple times at an identified place on a specific chromosome.

For example, one of the core STRs used in forensics in the U.S. is called D5S818. It's on Chromosome 5 and consists of a sequence of four DNA letters: ATCT. That ATCT pattern is known to repeat, one set right after the other, from 7 to 17 times. When test results come back, D5S818 will show two values, like 10-12. That means (aside from a possible current-generation mutation, or change) an inherited pattern of 10 repeats came from one parent, and 12 repeats from the other.

STRs will change by-generation far, far faster than the SNPs (single nucleotide polymorphisms) that our DTC tests look at. That's why STRs are used in forensics and paternity cases, and never our SNP tests done on a microarray chip. STRs can't even be guessed at from the raw data in our genealogy tests.

Our DTC tests look at only about one DNA letter in every 5,000. Pretty spotty stuff. But it works for genealogy thanks to something called genotyping. All humans have DNA that is a fraction over 99% identical. There are around 25 million SNPs that any two of us might differ on, and within similar global populations--say, Northwest Europeans, for example--that per-person difference may be as small as 4 or 5 million SNPs. So when the companies look at the 600,000 or so SNPs they use in our DTC tests, they infer what the untested, missing SNPs probably are based on our genotypes, benchmarks based on standardized genomes, even though those SNPs were never tested. When we see a DNA segment reported that's 20cM in length starting at position X and ending at position Y, that's never entirely accurate because we looked at only a few thousand of the markers along that physical segment which could be well over 20 million markers long.

That's why our DTC tests are not, and almost certainly never will be, used for forensics in a court of law. I believe cases like the Golden State Killer and Cece Moore's television show, The Genetic Detective, have caused some confusion about that...as shown by the slowdown in DNA test sales growth numbers following the GSK case publicity in 2018.

But Cece and company never provide court-admissible, convicting DNA evidence. She can't. What she does do is perform the same kind of genetic genealogy research we all can, e.g., if I know who Person A is, and there's a match in unknown Person B, let me try to trace the family trees to see if I can guess who B is.

In one of my trademarked World's Worst SimilesTM: It's like law enforcement knowing where and when a crime was committed, and that a car was most likely employed in the crime. Cece will go in and use her analytic skills to uncover that a Toyota Corolla with a license plate starting with an "S" and ending with a "35" was probably in that place at that time. What she uses as genealogical evidence never goes to court. But law enforcement can then decide whether they want to act on the clue provided and obtain an admissible DNA sample that can be subjected to an admissible CODIS-standard STR test. That's what is submitted as the DNA evidence.

Whew. A tour you never asked for. And with all that said, as technologies continue to improve and the effective costs lowered for high-throughput, high-accuracy, long-read whole genome sequencing, it may eventually supplant today's STR tests for forensics. But that will be a long time coming. We'll be using the technology for genealogy long before law enforcement...because they've been amassing databases of STRs for over three decades, and because such a change across law enforcement agencies will, bureaucratically, take a very long time and cost a very pretty penny.

Wow! Excellent explanation Edison -- even if a bit much for novices. Perseverance is the key for both learners and teachers. After 10 years of reading and wondering about all those numbers, I find that, gradually, bit by bit, the jargon and complexities begin to make logical sense, thanks to teachers like you who give time and effort to us who need help.
Thanks for that information. The actual science behind genealogy is very intriguing to me, I am just now starting to learn these things. Your answer is has sparked more energy to put forth in learning more about it. Thank you for that. I want to be able to answer questions that way one day lol.

5 Answers

+10 votes
Best answer
Technically there is no one "best" company to use.

But there are certain factors to consider.

Ancestry and 23 & me require you to spit into a tube.

My Heritage and Family Tree DNA only need cheek swabs.

Also Ancestry and 23 & me have large databases that are geared mostly towards Americans.

FT DNA and MY Heritage have smaller databases that have a lot of records and names from other countries outside the USA.

These 2 factors played a part in my own decision to use FT DNA and My Heritage DNA kits for me and my family. For the record, my family and I are not Americans.

PS, you should also wait for the sales. You can sometimes make some significant savings!!
by Robynne Lozier G2G Astronaut (1.3m points)
selected by Tiffany Knight
Thank you.
Be sure the Company you choose allows you to download your data. The mentioned companies do, but another one advertising right now does not.
Thank you. What company does not?
More than one I sawacomparison onliine. I actually paid for a test with CRI Genetics and then discoveted you couldnot download raw DNA. I got a refund.but had to pry it out of them.
Oh wow. At least you did get the refund though. Thanks for the advice!
+9 votes
And if you have the datas you can extract the raw data and raw datas you can paste them into other DNA-bases like Gedmatch,  yourDNAAportal, My Heritage and others to see if there are also matches.
by Dieter Lewerenz G2G Astronaut (3.1m points)
+13 votes
You have tagged your question mitochondrial. If by that you are planning to have your mtDNA analyzed the best site will be a site, where they analyze for that! And FTDNA is the only of the major companies that does that thoroughly. You can upload your autosomal results to some other sites.
by Ole Selmer G2G6 Mach 4 (42.4k points)
+5 votes
For autosomal DNA, consider:

- Ancestry has a vastly larger database (for matches) than MyHeritage or FamilyTreeDNA, and also larger than 23andMe.

- Your Ancestry DNA file can be imported into MyHeritage, FamilyTreeDNA and GEDmatch for free, to match against their database. You cannot import data the other way into Ancestry or into 23andMe from the others.
by Joe Murray G2G6 Mach 8 (84.6k points)
Thank you that makes things easier being able to import through all the others. Ancestry it is then.
Also Ancestry is the only one with a large database of genealogy trees. Thrulines helps you find out where you match.
+11 votes
More important than where you test is who you test.  If you're interested in genealogy and not entertainment (i.e. ethnicity estimate), you will get twice the information by testing your parents instead of yourself.  Of course it will cost twice as much and isn't always possible, but it's incredibly valuable for genetic genealogy.  Also, you want to test any living grandparents, and aunts and uncles when grandparents aren't available and the budget allows.  It's fine if you just want to test yourself to begin with to see how interested you are in doing genetic genealogy.  If you do get immersed in it, it's critical to test the others while they're available (i.e. alive and willing).
by Kerry Larson G2G6 Pilot (237k points)

As far as the test to choose, see Edison Williams' post, If you haven't tested with AncestryDNA, should you do it right now?

good point I didn't think that my mothers youngest brother is still alive and he is the last of that generation
If you want to learn more about your mother’s direct paternal line, then be sure to order a Y-DNA test from Family Tree DNA or YSEQ.  

Family Tree DNA stores the DNA of Testees which allows for additional testing as technology improves.  Y-DNA tests should be uploaded to mitoYDNA.org.  Family Tree DNA ‘s Family Finder (autosomal DNA test compatible with AncestryDNA) test should be uploaded to GEDmatch.com.

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