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


WHAT ARE THE DIFFERENT DNA TESTS AVAILALABLE?  
AND DOES IT REALLY MATTER WHICH TEST AND WHICH COMPANY I USE?


YDNA TEST

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.  Every 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)
        DNA Testing for Genealogists - a great video


mtDNA TEST

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 mother)  - and  every person in this ancestral link must be female.

Further Info
        Click Here


AUTOSOMAL  DNA testing

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 generally 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


OTHER CONSIDERATIONS

HAPLOGROUPS
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 ancestor 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


FINDING COUSINS
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


WHICH COMPANY TO USE?
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 equal 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:
http://genetics.thetech.org/ask-a-geneticist/same-parents-different-ancestry

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