Two years
ago I gave my brother a DNA test for Christmas.
In my defense, 1) it wasn’t his only present, and 2) even though it
seems like I bought a gift for myself, we really do have a mutual interest in
finding out more about our Smith line. I
was born a Smith, and my brother is still a Smith, making him perfect for yDNA
testing.
I have
always loved genetics. I remember
learning in school about Gregor Mendel, the monk who tracked the inherited
traits of peas and became the father of the science of genetics. I even liked doing Punnett squares, those
little graphs that predict the traits of offspring of a particular set of
parents. When I became interested in
genetic genealogy, I had to do homework again--about what tests are available
and what they can tell you about your family tree. The field of DNA testing has new developments
all the time, and I’m still learning about testing and interpreting test
results.
The first
test I took myself was a mitochondrial (or mtDNA) test. Mitochondrial DNA passes from mother to
child, uncombined with the father’s DNA.
Only daughters can pass it on to their children, so what mtDNA does is
trace your matrilineal line, your mother’s mother’s mother’s mother, back into
the distant past. Since a woman’s
surname usually changes in each generation, it can be difficult to use mtDNA to
find ancestors by name. What you get
instead are haplogroup matches—others who show the same mutations from the
original mother of us all, who the geneticists call “mitochondrial Eve.”
My
haplogroup is T, one of the 7 or 8 groups that are really common in
Europe. One of the first companies to
test mitochondrial DNA for the general public was Oxford Ancestors. You may have heard of its founder, Dr. Brian
Sykes, because he wrote The Seven Daughters of Eve, in which he explains
mtDNA testing and describes the seven clan mothers from ancient Europe who
still have descendants today. My clan
mother is Tara, who lived about 17,000 years ago in northwest Italy. (Geneticists look at how Tara’s ancestors
dispersed and how many mutations have occurred in her line to help them
estimate where her clan began and how long ago they lived.) Really cool, but not especially useful in
helping you fill out your family tree.
Back to my
brother’s Christmas gift. His paternal
line consists of our father, Jack Francis Smith; his father, Weaver Harris
Smith; his father, Stephen Albert Smith (for whom my brother is named); and his
father, John A. Smith. Yes, that’s
right—John Smith. That’s as far as we
know, and all we know about John A. Smith is that he was born about 1805 in
Virginia and died about 1850 in Pike County, Alabama. We hoped that my brother’s yDNA test would
help us differentiate our John Smith from the many others with the same name
and lead us to his parents, grandparents, etc.
While mtDNA
traces the matrilineal line of both men and women through mitochondrial DNA,
which both sexes have, yDNA traces a man’s patrilineal line, his father’s
father’s father, etc. through the genetic information encoded in his
Y-chromosome. While a man can take an
mtDNA test, a woman cannot take a yDNA test for the very important reason that
she doesn’t have a Y-chromosome to test. yDNA is a lot more useful for identifying
ancestors because surnames remain the same from generation to generation.
Hopefully, we would connect with another Smith (we joined a surname project
called Smiths Worldwide) who matches my brother genetically, and maybe he knows
who John A. Smith’s father was. Mystery
solved.
Except my
brother’s closest yDNA matches—he matches one of them on every one of 37
markers—are three men named Banks.
What?? I assumed the worst—what
genetic genealogists call a non-paternity event (NPE). I figured that sometime, somewhere, a female
married to a Smith was unfaithful with a Banks man, and the result of that
union took the surname Smith. I even
looked for Banks families that lived near our Smith family in Pike County,
Alabama, although I don’t know that that is where the alleged NPE took place. (There actually was a Banks family in Pike
County, but now what do I do with that information? The family tree of that Banks family doesn’t
match the family trees contributed by the Banks men who matched my brother on
the yDNA test.) So, there the results
sit, on the Family Tree DNA site, just waiting for additional information that
makes sense of them.
Until this
week, when one of my Internet cousins suggested I read a blog by genetic
genealogist, Roberta Estes, at www.dna-explained.com.
In fact, I have read the entire archive of her fascinating blog posts,
but one post, “Surprise Y Matches—What Do They Mean?” has been especially
helpful. According to Roberta, there is
more than one reason that one man might have matches with another man with a
different surname, and this occurrence is not that uncommon.
The fact
that my brother and Mr. Banks match at 37 markers means that they have a common
ancestor at some point in the past.
However, it’s possible to test 67 and even 111 markers. If my brother and Mr. Banks were to upgrade
to more markers, some mutations might show up that suggest that their common
ancestor is not recent but way further back in time. Testing of other cousins might prove either
line and show that what we are dealing with really is an NPE. Roberta also suggested what I had already
done—look for Banks families in proximity to our Smith families in locations
where we know they lived.
Other
reasons for the mismatch in surnames? 1)
Someone just decided to change his last name. (What better name to change to than Smith?) 2) A step-father raised a boy that took his
name, rather than his biological father’s.
3) A boy took his mother’s maiden name, perhaps because he was
illegitimate. 4) Someone was
unfaithful. And something I actually had
not considered—that the NPE, for whatever reason, might have occurred on the
Banks side, not the Smith side. Before
DNA, those circumstances might never have been suspected, and the answers would
never be found.
The recent
sale at Family Tree DNA ($99) has encouraged my brother to purchase the Family
Finder test. I’ve already had the FF
test done but have yet to find any conclusive Smith or Banks cousins. Family Finder finds matches through a third
type of DNA—autosomal. This is the DNA
that most of us are familiar with from those Punnett squares, the kind that is
contributed by both father and mother and combines in different ways to make each
of us the unique person that we are.
The
test produces a lot of data that I am still learning to interpret, but Family
Finder does a lot of the work for you by listing your DNA matches, typically
cousins and their suggested relation to you—2nd-3rd
Cousin, 4th Cousin, etc. Our
hope is that my brother’s test may give us some more options to trace our Smith
line. Because of the nature of autosomal
DNA, my brother may have inherited more on our father’s side and will show up
with more conclusive cousin matches that will give us some clues about the
ancestry of John Smith (or, I suppose, prove that we aren’t related to him at
all.)