Common Questions About DNA Testing for Genealogical Purposes
including some common misconceptions

In my observation of DNA testing among the Yancey Family - I  often find that people  purchase and use a genealogical  DNA test - - often without even really knowing what to expect – or without having a specific goal  or item to prove/disprove.  Also people often just purchase the most commonly available test or the cheapest test (such as ancestry.com) – having no clue how it might be different if they used a different company or different test type.   Knowing what your goals are in DNA testing and becoming familiar with the different tests and which companies provide each test – can make the difference between you reaching your goal – and you just wasting your money.

Also many people have misperceptions about DNA testing and how to interpret DNA results - below are some discussion of common misperceptions.

DNA 101



YDNA (Paternal Line) DNA testing is used to test the DNA that men inherit (near perfectly) from their Father (and thus from their paternal line direct male ancestors).  These results can then be compared with another male who has been tested to see if the results indicate a match (near match).   Any results can be matched with other testers resulting in a statistical probability that they have a common male ancestor on their paternal line.  Matches within 8 generations or so are pretty black and white would have a very high statistical accuracy.

Who would choose this type of test?

The main purpose of a YDNA test is to prove that two testers have a common paternal line ancestor – and since surnames are usually carried on the male paternal line – it is often referred to as the DNA for that surname.   The test can only be done on males.   It was this test that first proved that the Yancey family and the Nanney family do not have a common male ancestor – biologically speaking – because the YDNA of Yanceys and Nanneys was drastically different (even different haplogroups).

This test usually costs about $150  - varying from one company to the next as well as the number of markers tested.  ANCESTRY.COM – has NOT provided YDNA testing for quite some time now.
I suggest the use of Family tree DNA for this test (for the main reason – that so many other Yanceys have also used this company  – and you will be able to directly compare against their results - - which might not be possible if you use a different company)

To see the results of various Yanceys (and Nanneys and others) who have taken the YDNA test
See this page and test result   (be sure to note the scroll bar in the result window)

Note that when we say "paternal line"  we are only talking about the individuals who make up the link as we go on a pedigree chart  from son to father, to grandfather ad infinitum. . . .  (with a male ancestor at every single link)
It does NOT mean all the ancestors/DNA of one's father.  E
very single person in this ancestral paternal line link must be male - if it were not so - the YDNA would not have been passed down.

Persons who do have common Paternal ancestry within recent centuries - will have a virtual match.  People who may be related, but not via the single paternal line, but via some other line will NOT have a "sort of match"  - rather they will have a total NO Match.  Within recent centuries the indication of common paternal descent should be either black or white (yes or no).

Further info
        World Families
        YDNA  Success Story
        Results of Yanceys tested with YDNA test kit   (note scroll bar in window)


Mitochondrial DNA testing (Maternal line testing) is very similar to the YDNA(Paternal line) test – except the mtDNA test is based on DNA passed (near perfectly) from Mother to child.    Two persons who have a match on mtDNA have a common maternal line ancestor.   (mother of their mother of their mother . . . )  Both Males and Females can take this test.
ANCESTRY.COM – has NOT provided this test option for quite some time now.

Who would choose this type of test?

Because surnames don’t (normally) get passed down along the maternal line – the mtDNA does not normally apply to a specific surname.  Also due to how rare mutations are in the mtDNA - a common maternal ancetsor between two matched people - could actually be an ancestors a thousand years ago. For these reasons this test is normally much less used in the area of genealogy.  Though if the goal is to prove common maternal line of descent – the test is very conclusive.

Note that when we say "maternal line"  we are only talking about the individuals who make up the link as we go on a pedigree chart  from child to mother, to grandmother ad infinitum. . . .    (it does NOT mean all the ancestors/DNA of one's father)  - and  every person in this ancestral link must be female.

Further Info
        Click Here


Though many company’s may use different names for this type of test  (such as “Family Finder” or other names ) - - this type of test is based on a genetic testing known as autosomal DNA testing.   The most common Autosomal tester is probably ANCESTRY.COM - and for some time now it has been the ONLY test they provide.

Contrary to YDNA and mtDNA  (which are tests that apply to a SINGLE line of descent paternal/maternal) - - the autosomal  test results apply to DNA inherited from your ancestors as a composite whole.   The autosomal test is often provided with results that attempt to indicate percent ethnicities or percent countries of ancestral origin.  Though the truth is such results are often provided in way that is often misleading and even on the verge of untruthful.  One has to use real caution in interpreting ethnic / geographic results.

Even though the enthnic reporting provided can be of limited value - - there are still some significant reasons one may wish to take an autosomal DNA test.  One of these reasons is the ability for you to find DNA matches between you and other testers that indicates a common ancestors.   Matches between two people based on autosomal testing – are pretty reliable as to the fact that a common ancestor/family line exists between such testers.   HOWEVER  -  the test itself – does not explicitly prove what specific LINE/ANCESTOR the common match is originating from. To do this requires additonal detective work.

DNA companies supplement this autosomal DNA match with genealogical databases that attempt to show where in the family tree the common ancestral line is found.   However such genealogical databases  may either be imperfect/incomplete and may not go into time periods where the match actually occurred.  It is quite possible that two people matched may make incorrect assumptions as to who the common ancestor is or they may not be able to determine exactly which surname is the common link. 

Who would choose this type of test?
People would choose the autosomal test if they want to get some idea of very general ethnicity/geographic components  though such results are nowhere near perfect – and do not normally contain any “time factor”  (at what point were my ancestors among this ethnic group or this geographic region?)    Also people very often mistakenly assume it very much applies to their surname line – when in reality it is a composite of all of their ancestors  (of which their surname line – is only one of millions of other family lines they descend from).  
The  fact is - most people already have a pretty good idea as to general ethnicicty background - and the ethnicity test result may not really tell them much than what they already knew.  However DNA companies will also provide mathing DNA reports - showing what other testers you "match" with - and allow you to make contact with these matches.  This is one of the main reason to take autosomal DNA testing.

People might also take the autosomal test because they are looking for a match between two  family groups – that DONT share a YDNA/mtDNA link - - but are suspected to be related via some other line in the family tree (other than the paternal or maternal). 
Autosomal testing is less restrictive  than the YDNA. mtDNA tests (a gwenral good thing) -  though the results may be more ambiguous  (a bad thing).
The autosomal test usually costs about $100  - and is usually the cheaper test that people may find in their on line searching.   But make sure it is right for you - or you may find it didnt help you accomplish your goal and you might have to retake a different test.

Some Peoples experience with autosomal testing:

        DNA Success Stories
        "Young & Savvy"
        Took Test Twice
        "Gone Fishing"
        Tips on making contact with autosomal matches


With both YDNA and mtDNA testing - - - testers are usually categorized into one of a small set (less than 25) of what are called “Haplogroups” – which attempt to show different branches of the genetic branches of human descent (an extremely high level view of the world family tree).   People with the same Haplogroup – would have a common ancestors at a much nearer distance – as compared to people who have two different Haplogroups.

But scientists believe haplogroups trace back THOUSANDS of years - - so one should NOT assume that such common haplogroups and corresponding geographic regions shown in test results based on Haplogroup  represent where their immigrant ancestor  directly came from when arriving in America.   In other words - a map showing your Haplogroup concentrated in the area of what is now Turkey - does NOT mean your ancetsor who immgrated to America 200 years ago came from Turkey. And it might not even mean that any of your direct line ancestors lived in Turkey - since most Haplogroup charts are based on results of people who CURRENTLY live in a given area.  (most charts dont take into consideration human migration over the centuries and millennia)
Also note it is a different set of Haplogroups for YDNA versus mtDNA
Haplogroups Explained

Some people will use DNA testing to find "cousins" who they match with.  This will often be the most common reason for DNA testing. Its  quite possible you may find cousin matches you would not have found elsewhere.   BUT don't think DNA testing is the necessarily the best or quickest ways to find cousins. There are certainly many other means to find relatives these days - especially with the use of the Internet.  Though it is true that DNA matching may/can put you in contact with various people you would not have found in more traditional means - it is not a silver bullet.  Also of note is that even though some DNA company may give you pages of  "potential matches" - it is quite possible that you may not have success in trying to contact many of the persons on your match list. And even if you do - - the location on the family tree of the exact connection may be totally uncertain.  each person's experience with DNA testing will be different. 

 Tips on making contact with autosomal matches

Many people just compare the cheapest prices among differnet DNA testing companies and select the cheapest.  People often choose Ancetrey.com due to lower cost.   But all too often they later realize that the test they took - wasnt the the test they really needed to take - to find out what they were trying to discover.  And then they have to pay more money for a different company to do a different test.
Understand what your goals are before ordering a test.

Sorting out the DNA Tests

Our Genetic makeup - some helpful metaphors
One analogy/metaphor  that I really like to use when discussing the DNA that we inherit from our ancestors  - is to compare it to a very very large ROPE of many different (millions) of colored small individual threads.   Each thread has its own unique color/character.  But the rope as a whole has its own unique characteristics.   I realize that often metaphors don’t perfectly match reality – and this is no exception.  But the emphasis here is that we are all the product of millions of different ancestors/family groups.  As a sample scenario -  people are often quick to take the Ancestry.com  DNA test - - and then when they get their results - - expect that it applies  to their Surname family line ("The Yancey Family").  The truth is our surname line is only  one of millions of family lines – and as so the DNA we would inherit from some immigrant Yancey ancestor as an example – would only be one of many thousands of ancestors and thus would only make up a very small percentage of our DNA  (less than 1%) - --  thus Autosomal results cannot apply to any single one family line - - -they apply as composite info – as to your family tree as a whole.

Also to consider.  Though I really love this metaphor of a rope with threads for each family line - - as our DNA inheritance  -  - it should also be noted that even among siblings with the same exact mother and father – the threads and composite ”rope”  each child inherits are NOT identical  (that’s why one sibling can look very much different than another sibling).   Though each of a set of siblings inherits 50% of their DNA from their father and 50% from their mother  - - they do NOT inherit exactly 25% from each grandparent. It’s a random selection from the grandparents DNA that was pased on to the parent.   Thus going back to the rope metaphor - - each child will have different size threads or maybe better stated – a different sub-set of threads than what other children inherited from their parents.
As a result of what was just stated - - one must realize that DNA testing results in the autosomal test  (even if perfectly accurate – which they are not) – DO NOT actually represent  the accurate family tree  of the tested person as shown on their pedigree chart.   RATHER they represent the DNA/Genetics that the tester actually DID inherit from their ancestors  (or not)  - and thus the actual inheritance – may not match  (will not match) the results if the person had inherited DNA from all of their ancestors in a perfectly equal portion.  Descendants don’t actually inherit DNA from their ancestors in perfect  equalk proportion - - though the averages over time and people – may correspond to the stated expectation.   This is one reason that one family could actually have a small  portion of Native American ancestry - -  and yet one child may show it in their results and another child not.  Autosomal results among siblings are not identical.   Contrastingly YDNA results among male siblings would be near identical, as well as mtDNA results. (the latter two only NOT being perfectly the same – under the case of random mutations that can rarely occur between Parent and child)
Here is an interesting discussion:

For more details: about genetic testing you may wish to visit these sites:



Some common misperceptions about DNA testing:

#1  DNA Tests are expensive.
      Answer: It depends

"Expensive" is a relative term. DNA tests can start at about $70 and go up to about $400.  BUT two tests that have a significant price difference - are normally two  different test types - with valid reasons for price difference.   Things that control price usually include test type, and numbers of markers tested.  I do not recommend people simply start with the cheapest test and see how it goes.  Nor do I recommend people take a DNA test simply because "everyone is doing it".   I recommend that people take a test after analyzing the different types of tests that are available and see which one best meets their goal - which may not be the cheapest.  And if they don't have a specific goal  in mind - - then I question if they should really be taking the test.      Selecting the cheapest test for no other reason than price - may simply be a waste of money.

#2  Genealogical DNA tests are the same thing as what you see that CSI Investigators use.
    Answer: False.


Genealogical DNA tests are not the same as the type of tests used by CSI investigators.  Genealogical DNA tests use a mouth swab to gather the DNA sample - and DO not use  things like blood, hair or tissue samples.  Genealogical DNA tests are for the living (not the dead) and are used to help indicate common ancestral lienage between two testers.    Since certain types of DNA are passed down from parent to child with near perfect replication - we can indirectly know the DNA type of some of our deceased ancestors.   CSI type DNA tests are usually much more expensive.  Paternity testing is also not the exact same thing as genealogical testing - though similar.

#3  DNA testing will open me up to identity theft or "Big Brother"
    Answer:   Far exaggerated.

My general impression of people that have this line of thought is that  they are far exaggerating possible negative implications of DNA testing.  Identity thieves and related malfactors often use things like SSN's, birthdates, credit card numbers  and similar items to steal identities.  Such information is either not gathered at all by DNA tests, or in the case of credit  cards is not normally kept on file.  In my humble opinion people are thousands of times more likely to experience identity theft by simply using a credit card in a restaurant, than they are  by doing a DNA test.  The results of a genealogical DNA test - would be of no significance to  an identity theft.  Also the government and big brother do not own these DNA companies.  And one should realize that even if we submit a sample for DNA testing - in most cases we are  still in control of our sample - and can have it destroyed upon request. Just like money in the bank  is still in our control - our DNA sample is still in our control. 

However one possible negative impact that can take someone totally by surpriseand that many people dont consider  -  are DNA test findings that may indicate something that was totally  unexpected. For example - the discovery that a given person was not the biological child of the parents assumed as biological parents.  It can be a total shock to a tester.

#4 DNA testing will allow me to more fully fill out my family tree chart.
    Answer: FALSE and TRUE

Directly speaking - NO, a DNA test, by itself,  will not provide the names for your ancestors.   BUT because of the things that are revealed - and information about people you match with, coupled with information gathered through genealogical research-  a DNA test can indirectly  provide clues that do help you find the identity of your ancestors. BUT genealogical DNA testing  is NOT a silver bullet that magically fills out your pedigree chart all by itself.

#5  - It is easier (& less sostly) to prove that two people are not related than to prove they are related.
    Answer:  TRUE

Interestingly - TRUE.   Case in point was the 2013 DNA testing that was done between members of the Yancey Family and members of the Nanney Family -  with a simple 12 marker YDNA test  (I think it was only about $50 per test). As a result of this test - it was easily  discovered with little cost - that the Yancey and Nanney male line descendants do not share the same Haplogroup  (DNA Grouping) Yancetys were J2 and Nanneys were R1.  Based solely on this simple discovery it was conclusively ascertained that the Yanceys and Nanneys tested do not share a common paternal line ancestors within recent centuries. However to prove that two people do share a common ancestor would take a comparison of more DNA markers (preferably at least a 37 marker test )  and a near match on all 37 markers. 

#6  - DNA Testing will tell me what country or region
 my immigrant ancestor came from??
        ANSWER:  FALSE

Though autosomal testing may give you some  general ideas at a very high level what region of the world your ancestors (as a whole) may  have come from
(using probability statistics) . They cannot tell you what country one specific American immigrant came from or even one ancestral line.  Many Americans actually have hundreds or even thousands of immigrant ancestors - -each one with only a minute portion of their DNA being found in the currently living descendant (if any at  all).

DNA doesn't respect political borders.  People born in a given country - dont magically get endowed with a certain set of DNA. Though it may be true that certain DNA types are found with prominence within a given country or region. But as a person or family migrates from one country or region to another - its not like their DNA changes to match the region.   There is no way that DNA can prove or control - - where a specific given ancestor lived.  Though it might be true that we can use probability and statistics to come up with a probability that our ancestors came from a certain region - the rules used in such analysis are very imperfect and are inconsistent from one company to another.

Most DNA ethnicity reports don't take into consideration human migration and changes in political borders over time.  Actually what many people dont realize is that these ethnicity reports are normally  based on comparisons to DNA tests of LIVING people around the world - whose DNA results have been stored in a large database and this database used to generate DNA ethic groupings.   But where these people live today - may be totally different than where there ancestors lived 500 years ago.  There have been over time - many major migrations - not all of which are well documented.   A given single family line - might trace from the area of the Middle East,  to France, later Britain, then America and maybe even later Canada.   How does this get reflected in the ethnicity reports??  (It doesn't)

Note that even among siblings - who have the same  mother and father - there can be significant differences as to Autosomal DNA Ethnicity reports.  Some people have claimed as much as a 10% difference in percents among siblings tested.  Thus any percent less than like 10% could simply be due to sibling variance - and may not reflect the true percentage of a family pedigree.  This is mainly because though siblings inherit DNA from the same parents  at 50% each - it is not the same 50%, but a randomly selected different 50% for each child  - thus each sibling will inherit differing portions of DNA from the four grandparents.  And there will be some DNA in each ancestor - that just never makes it from grandparent to a given grandchild.

Because only certain DNA is passed from one generation to the next - - the DNA that a descendant inherits is not an equal proportion of all their ancestors. There may be ancestors who's DNA footprint in a given descendant is so small it is effectively non existant.  Autosomal DNA testing will only show porportions of Ethnicity based on DNA that was actually inherited.  This is why even if a person had 1 Grandparent with 100% British DNA, and  another with 100% Scandinavian DNA, and  another with 100% Russian,  and the last with 100% Asian - - - if autosomal testing was done - - chances are low that they (the grandchildren) would report exactly 25% of all of these ethnicities.  And if there  were siblings - each sibling would report a unque set of percent ethnicities.

Note that there is no time frame given the autosomal DNA reports as to what time period ones ancestors came from a specific region or ethnicity. Was it 50, 100, or 1000 years ago that  my ancestors lived in these regions?- DNA tests would not normally have any time factor - and without the time factor - - their use for genealogical purposes becomes very limited.

Note that even if a DNA Testing company reads your DNA markers with 100% accuracy - which probably isnt that far off from reality.  Even so - that doesnt mean that the inferred results of those markers will be interpeted the same by differing companies.  Such is especially true of autosomal ethnicity reports.   There is nothing on your DNA that yells out "Hey - I am Irish DNA, or I am African DNA" - there is no golden standard of rules that companies must follow to derive the ethnic percentages from the known DNA marker values.  For this simple reason - differing companies can give differing results on the ethnicity of your DNA - even if they both read your DNA markers with perfect accuracy.  Interestingly even with the same company you can get different results on subsequent testing and is probably mainly due to the the fact that simply their subjective and imperfect rules have changed for how to interpret results. As the databases of  DNA companies get bigger - and the rules they apply become more complex - - the results they report - even on the same DNA sample can change.

Not all companies use the same granularity as to DNA ethnic origin.  For example some companies may simply divide the African continent into  various regions - while other companies might try to use the granularity of current political boundaries of  African nations  (which didnt even exist politically speaking 200 years ago).  Don't just assume that because one company reports a more specific location means that the report is more accurate - - it actually may be the contrary.

Be extremely cautious when geographic statistics of origin are used on YDNA or mtDNA results or haplogroups (versus autosomal)  - since such results only apply to one ancestral line among  thousands or millions.    People are the product of all their ancestors - not just the paternal or maternal  line.

Realize that many news stories are more hype than fact - - such as news stories about test-takers such as Oprah Winfrey learning she is Zulu or a Floridian accountant being told he descended from the Mongolian warlord Genghis Khan.

All so often people think "oh that's cool that I have these percentages of ancestral origin"   - - - but in the end - -  virtually nothing comes of it in the long run (or even the short run) as to making any genealogical progress. And oft times its nothing they didnt really already know for the most part.

I do believe there are some very legitimate cases for taking autosomal DNA testing  - but my faith in any real significance as to ethnic origins  is extremely small.  Unless maybe you were adopted and had no clue at all as to origins.

Autosomal Testing can provide some cousin matching results that can be very helpful in specific cases.  But all so often I feel people take the ancestry.com autosomal report - only later to wish they had taken a YDNA paternal line  test (due to their hope of proving common paternal ancestry with other Yanceys).  It just depends what your goals are and what your limitations are (not all tests can be taken by everyone).

Be cautious of the phrase "DNA DOESNT LIE".  Though I do agree that genetic markers can be read with an extremely high degree of accuracy.
That doenst mean that DNA companies dont make the results seem like it means one thing when it really doesnt.    (especially in the area of ethnicity and origin)
Give a single DNA report to 10 different people - and you'll probably get 10 different mis-assumptions or misperceptions.
And who is out there to rate the accuracy of DNA company test results ??   Not enough people . . ..