Test them all!
The one thing that is abundantly clear is that understanding DNA testing and the way it can be used in genealogy is tough stuff.
We have to understand what kinds of DNA tests there are.
We have to understand what those tests can and can’t show.
And we have to understand who to test to get the most from what the tests offer.
Compared to that, understanding those tick marks on an early census record seems easy!
And it’s that complexity that’s tripping up reader Gail as she tries to figure out who to test right now — herself or her brother.
“I am still wondering,” she wrote, “if I want the most complete results -– would it be better to test my brother versus myself as a female? Although I am reading it makes no difference it did make a difference with National Geographic since we got the female line only with myself and had to test my brother which resulted in duplication of the female with the addition of the male. Also, since the male or female DNA results showed only the direct line, will that change for the DNA tests from the other sources?”
Clearly some confusion going on here, so let’s go back to the basics and review the three basic types of DNA tests.
First, we have YDNA — the kind of DNA found in the male gender-determinative Y chromosome that only men have.1 It gets passed from a man only to his sons and from his sons only to his grandsons and from his grandsons only to his great grandsons, with few changes down the generations.2
That’s the test Gail’s brother has already taken with National Geographic, and that gave him what she refers to as “male DNA” results. That tells her and her brother only about their direct paternal line: their father’s father’s father and so on (plus all of the sons and grandsons of those men) share the same YDNA.
What does that type of test tell us? It can help us answer a key question: am I descended from — or at least related to — that one man? So it’s an excellent test for genealogists, but for this test they have to have a male candidate to test.
Second, we have mitochondrial DNA, or mtDNA — the kind of DNA we all have that serves as the energy producer for the cells in our bodies.3 It gets passed from a mother to all of her children — male and female — but only her daughters can pass it on to her grandchildren.4
That’s the test that Gail and her brother have both taken with National Geographic that she’s referring to as the female line because it tells them about their direct maternal line: their mother’s mother’s mother and so on (plus all of the children of all of the women in a direct line of descent) share the same mtDNA.
What does that type of test tell us? It can help us answer a key question: am I descended from — or at least related to — that one woman? It’s a tougher test to figure out because of the inheritance pattern: you can test a son if you’re looking for information about his mother’s mother’s mother’s line, but you can’t test that son’s children since they have the mtDNA of their mother, not their father. So it’s an excellent test for genealogists, but only if they have the right candidates — male or female — to test.
Third, we have autosomal DNA — the kind of DNA we all inherit from both of our parents5 in a mix that changes, in a random pattern, from generation to generation in a process called recombination.6
That’s the test that Gail is really asking about right now, and wondering whether she or her brother would be better to test — and whether it makes any difference who gets tested.
What does that type of test tell us? It tells us about all of our ancestors back within four or five generations, to help us answer the question: am I descended from — or at least related to — that couple? So it’s really most useful for finding cousins who share some portion of DNA with us with whom we can then share research efforts.7
And because that recombination bit happens every single time a child is conceived both Gail and her brother should be tested. Recombination is purely random, so Gail could well have inherited some fairly substantial chunks of DNA that her brother did not inherit — and vice versa.
And to be sure of getting the most from autosomal testing, not only should Gail and her brother both test, but they also want to test everyone else in the family — parents or grandparents still living, other siblings, aunts, uncles, cousins — that they can convince to test.
Each family member will have cousin matches in the DNA testing databases that the others won’t have — and some of those individual matches may provide the keys to some enduring family history mysteries.
Bottom line: when it comes to autosomal testing, test everybody you can afford to test!
SOURCES
- ISOGG Wiki (http://www.isogg.org/wiki), “Y chromosome,” rev. 18 Jan 2015. ↩
- Ibid., “Y chromosome DNA tests,” rev. 27 Nov 2014. ↩
- “What is mitochondrial DNA?,” Genetics Home Reference Handbook, National Library of Medicine, US Department of Health (http://ghr.nlm.nih.gov/handbook : accessed 18 July 2015). ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Mitochondrial DNA tests,” rev. 15 May 2015. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Autosomal DNA,” rev. 30 June 2015. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Recombination,” rev. 14 June 2015. ↩
- See Judy G. Russell, “Autosomal DNA testing,” National Genealogical Society Magazine, October-December 2011, 38-43. ↩
Great explanation, Judy!
Am I correct in thinking that there is an exception to the autosomal DNA “test them all” situation, that when you have had both parents tested, you don’t then need to test a sibling because they wouldn’t have inherited any DNA that wasn’t passed on to them by Mom and Dad?
If my sister, who was adopted, and my brother, who was not- were tested, what could be the possible results?
It will show whether they are — or are not — genetically related back to about the fourth or fifth cousin level. And if your adopted sister does not know who her biological parents were, it may help her identify them.
Where can I order these different DNA tests. I have purchased the regular test that Ancestry.com offers but did not know about these others.
Thank you.
Josephine Gonzales
YDNA and mtDNA tests for genetic genealogy are only available from Family Tree DNA.
Would like information on “Y” chromosome DNA testing…
Mitochondrial DNA testing…Recombination and Autosomal DNA…
Also where can I order these DNA test…Thank you…
Sounds like you need to do some reading up. You can read through the ISOGG wiki (http://www.isogg.org/wiki) — or get one of the DNA books now on the market like Blaine Bettinger’s new book (see the review here).
If 2 half-sisters test their DNA (they share a father, but different mothers), how would it be shown on the results? Would they be siblings, half-siblings, or would they even show up as related. They show up as first cousins to my husband.
Much would depend on which company they tested with. They need to look at their own results (against each other, rather than as versus your husband) and see what the results show. If they tested with 23andMe or Family Tree DNA, they will be able to see right in their results pages the total amount of DNA that they share and they should fall into the range of sharing roughly 25% (or about 1700 centimorgans). If they tested with AncestryDNA, they will need to use a third party site such as GedMatch to see precisely how much DNA they share.
Recently I learned that my biological father may – or may not – be
the father of a nice man who lives 3000 miles away. We clearly
have different mothers, so we would need to do the autosomal DNA
test.
Is it correct to assume that we both need to do a blood test, not just
the cheek-swab, in order to determine whether or not we are brother
and sister by the same father? What vendor should we go to?
How does one do the blood draw?
You absolutely do NOT need to do a blood test. You can do the swab test and be completely confident that it will show you if you are in fact half-siblings. The best test to take for this is the Family Finder test at Family Tree DNA, and it’s on sale right now for $89 plus shipping. The total amount of DNA you share will tell you if you both have the same father.
So, the only way to determine if my paternal grandmother was of American Indian descent is to have her daughters or granddaughters tested, correct?
My brother was tested and no American Indian was indicated.
No. Testing a direct female line descendant will determine if she had a Native American haplogroup, and thus point to Native American ancestry. But any of her descendants can be tested to see if there is Native American autosomal DNA. The older the relative, the closer to that grandmother’s generation, the better.
Will my brother’s DNA provide more information than mine, a female in regards to finding ancestors? I’ve done Ancestry’s DNA test and so has my mom.
Not the kind of DNA test that Ancestry does, no. Your brother may have a few more matches on your father’s side than you do, and so it might be worth testing him anyway, but the real DNA test your brother can take that you can’t is the YDNA test to disclose more about your direct paternal line (your father’s father’s father’s line). That test for genealogy is done only by Family Tree DNA.
Hello Judy,
I’ve done a lot of homework, and I understand from the article why the autosomal test is important for everyone in the family. However, I am still trying to understand if I should also do the mtDNA full sequence if my brother does it as part of the comprehensive male specific genome test at https://www.familytreedna.com/products# that includes the 67 marker Y-DNA. Since cost is an issue, will my brother doing the full complement of tests and me having just the autosomal get the picture I’m a hoping for? It seems from all I’ve read that my brother and I should have identical mtDNA and therefore I don’t need to take the test if he does.
Thank you so much for your insight!
If you and your brother share a mother, then only one of you needs to do the mtDNA full sequence test. Both of you should do autosomal, and he should do YDNA. That gives you the maximum amount of information you can hope for.
That is what I thought, thank you for confirming.
Should I have both of my sons individually tested (both from same parents)? My younger son just sent off his DNA with Heritage DNA. Thanks
It depends on what it is you’re trying to learn. But if you do decide to test them both, I’d test one of them with another company such as AncestryDNA for its deeper database of matches.
My sister and I have both already taken the autosomal dna test. There are websites which claim our two autosomal tests can be compared somehow to determine the Paternal Y of our father without my taking another, Y-only test; but they don’t explain how. Both our parents are deceased. How is this comparing a sister to brother’s test to determine Paternal Y done? Thank you.
If all you want is your YDNA haplogroup (I assume from the AncestryDNA test), you can follow the directions here: https://ytree.morleydna.com/extractFromAutosomal
If what you want is enough information to compare to other men using YDNA markers, you’ll have to do a YDNA test.
I am searching for anyone related to my father. I have taken the AncestryDNA test now I wonder should I test my sister or brother or my niece. my siblings and I all have the same mother and different fathers. I’m trying to cross out my mothers ancestors and focus solely on the other relatives. what should my course of action be??? I have an extra AncestryDNA test.
If you can test a close relative of your mother who is not also related to your father (one of your aunts or uncles or one of your mother’s first cousins, for example), then it will be easier to isolate the matches that are on your father’s side. Those who match you but don’t match that other maternal-side relative are candidates to be on the paternal side.
I did my test with the National Geographic Geno DNA Ancestry Kit. I am female. My Mother goes back at least 5 generations in Ireland and my Father at least 4 generations in Spain. My results showed 58% NW Europe 38% SW Europe and 2% Western Mediterranean. If my brother does the test will we get more information about my Father’s line?
Yes, because your brother will get his YDNA results that those reflect only your father’s father’s father’s (etc.) direct line.
Thank you so much Judy! We will use a different DNA service. I think we will use Family Tree DNA since, if I’ve understood correctly this is the most thorough.
You will certainly be able to get your brother thoroughly tested at FTDNA, yes — his YDNA (your father’s father’s line), his mtDNA (your mother’s mothers line — and you and your brother both share this) and his autosomal DNA (inherited from both parents).