This project is not part of Ancestry.com DNA sales. This project uses http://www.familytreedna.com Web space provided by rootsweb.com, sponsored by ancestry.com. Please read notice in the bottom bar. Advertisements at the top and bottom of the pages are not part of this project, visiting the links helps pay for the website space ~~~~~~~~~~~~ |
DNA
Testing for Genealogy - What Can It Do For You??
Paper courtesy of Roberta Estes, www.dnaexplain.com, e-mail Roberta at [email protected]. Graphics courtesy of Family Tree DNA, www.familytreedna.com.
(LOADS SLOWLY BUT WORTH IT) DNA
testing for genealogy didn’t even exist a few years ago.
In 1999, the first tests were performed for genetic genealogy and this
wonderful tool which would change genealogy forever was born for the consumer
marketplace from the halls of academia. Initially
we had more questions than answers. If
it’s true that we have some amount of DNA from all of our ancestors, how can
we tell which pieces are from which ancestor?
How much can we learn from our DNA?
Where did we come from both individually and as population subgroups?
How can it help me knock down those genealogy brick walls? In
just a few short years, we have answers for some of these questions.
However, in this still infant science we continue to learn every day.
But before we discuss the answers, let’s talk for just a minute about
how DNA works. DNA
- the Basics Every human has 23 pairs of chromosomes (think of them as recipe books), which contain most of your DNA, functional units of which are known as genes (think of them as chapters). One chromosome of each pair comes from a person’s mother and the other from their father. Due to the mixing, called recombination, of DNA that occurs during meiosis prior to sperm and egg development, each chromosome in 22 of the 23 pairs, which are known as autosomes, has DNA (think of it as ingredients) from both the corresponding parent’s parents (and all of their ancestors before them).
Two
portions of our DNA are not combined with that of the other parent. The 23rd
chromosome, in the green box above, determines the sex of the individual.
Two X chromosomes produce a female and an X and a Y chromosome produce a male.
Women do not have a Y chromosome (otherwise they would be males) so they cannot
contribute a Y chromosome to male offspring. Given this scenario, males
inherit their father’s Y chromosome unmixed with the mother’s DNA, and an X
chromosome unmixed with their father’s DNA. This inheritance pattern is what makes it possible for us to use the Y chromosome to compare against other men of the same surname to see if they share a common ancestor, because if they do, their Y chromosome DNA will match, either exactly or nearly so. Autosomal
DNA, X chromosomal DNA and, in males, Y chromosomal DNA are all found in the
nucleus of a cell. A a fourth type
of DNA call mitochondrial DNA, or mtDNA for short, resides within cells but
outside the cell’s nucleus. Mitochondrial
DNA packets are the cell’s powerhouse as they provide the entire body with
energy. For both genders, mitochondria DNA is inherited only from the mother. Men have their mother’s mtDNA, but do not pass it on to their offspring. Women have their mother’s mtDNA and pass it to both their female and male offspring. Given this scenario, women inherit their mother’s mtDNA unmixed with the father’s and pass it on generation to generation from female to female. (Males carry their mother’s mtDNA, but don’t pass it on.) This inheritance pattern is what makes it possible for us to compare our mtDNA with that of others to determine whether we share a common female ancestor.
These
animations at the Sorenson Molecular Genealogy Foundation website are an
excellent visual resource for understanding how the 4 kinds of DNA are passed
from the parents to a child. http://www.smgf.org/pages/animations.jspx Autosomal DNA (not the 23rd chromosomal pair) tends to be transferred in groupings, which ultimately give us traits like Mother’s blue eyes, Grandpa’s chin or Dad’s stocky build. Sometimes these inherited traits can be less positive, like deformities, diseases or tendencies like alcoholism. How this occurs and what genes or combinations of genes are responsible for transferring particular traits is still being deciphered. Sometimes we inherit conflicting genes from our parents and the resolution of which trait is exhibited is called gene expression. For example, if you inherit a gene for blue eyes and brown eyes, you can’t have both, so the complex process of gene expression determines which color of eyes you will have. However, this type of genetics along with medical genetics does not concern us when we are using genetics for genealogy, so we will focus initially on the unmixed Y chromosomal DNA, called Y-line for short, and mtDNA as genealogical tools. How
Can Unrecombined DNA Help Us With Genealogy? I’m
so glad you asked. During
normal cell meiosis, each ancestor’s autosomal DNA gets watered down by half
with each generation. However,
that isn’t true of the Y-line or mtDNA. In
the following example of just 4 generations, we see that the Y chromosome, the
blue bar marker on the left, is passed down the paternal line and the son has
the exact same Y-line DNA as his paternal great-grandfather. Similarly, the round doughnut shaped O represents the mitochondrial DNA (mtDNA) and it is passed down the maternal side, so both the daughter and the son will have the exact same mtDNA as the maternal great-grandmother (but only the females pass it on).
The
good news is that you may well have noticed that the surname is passed down the
same paternal path, so if this is a Jones family, the Y-line DNA travels right
along with the surname. How it can
help us with genealogy now becomes obvious, because if we can test different
male descendents who also bear the Jones surname, if they share a common
ancestor somewhere in recent time (the last several hundred years), their DNA
will match, or nearly so. Surname
projects have been created to facilitate coordination and comparison of
individuals carrying the same or similar surnames. Mitochondrial
DNA (mtDNA) is useful as well, but not as readily useful for genealogical
purposes since the surname traditionally changes with each generation. There
have been several remarkable finds using mtDNA, but they are typically more
difficult to coordinate because of the challenges presented by the last name
changes. Sometimes joining regional
projects is more useful for finding mtDNA matches than joining surname projects.
A case in point is the Cumberland Gap project which has helped many
people whose families lived in close proximity of the Cumberland Gap (at the
intersection of Va., Tn. and Ky.) connect with their genetic cousins.
What mtDNA can easily do for us is to confirm, or put to bed forever,
rumors of Native American, African or Asian ancestry. What
About Mutations? Another
really good question. Y-line
DNA testing actually tests either 12, 25, 37 or 67 locations on the Y
chromosome, depending on which test you select.
What is actually reported at these locations is the number of exact
repeats of that segment of DNA. Occasionally,
either a segment is dropped or one is added.
This is a normal process and typically affects nothing.
These repeated segments assure that if one segment is bad, another one
can take its place. However, for
genealogy, they are wonderful, as the number of segments in a particular
location will typically be the same from generation to generation. When
a change, called a mutation, does occur at a particular location, it is then
passed from father to son and on down that line.
That mutation, called a “line marker mutation” is then associated
with that line of the family. If
you test different individuals with the same surname, and they match except for
only a couple of minor differences, you can be assured that they do in fact
share a common ancestor in a genealogically relevant timeframe. A
father can potentially sire several sons, some with no mutations, and others
with different mutations, as shown by the red mutation bar in the following
illustration.
In
the above example, John Patrick Kenney had two sons, one with no mutation and
Paul Edward Kenney who had one mutation. All
of the male descendents of Paul Edward Kenney have his mutation and a second
mutation is added to this line at a new location in the generation above Stan
Kenny. John
Patrick Kenney’s son who had no mutations sired a son Joseph Kenney, who had a
mutation in yet a different location than either of the mutations in the Paul
Edward Kenney line. In
the span of time between 1478 and 2004, this grouping of Kenney/Kenny families
has accumulated 4 distinct lines as you can see across the bottom of the
diagram, line 3 with no mutations, line 1 with 2 mutations, and two other lines
with only one mutation each, but those mutations are not in the same location so
they are easily differentiated in descendants testing today. What
Do the Results Look Like? Results
are reported in the following format at Family Tree DNA where locus means the
location number, the DYS# means the name of that location, and the number of
alleles means the number of repeats of DNA found in that location. This is a partial screen shot from the Family Tree DNA
results page for a participant.
This
is interesting, but the power of DNA testing isn’t in what your numbers alone
look like, but in how they compare with others of similar surname. As
a DNA Surname Project Administrator of several groups, I combine the groupings
of participants into logical groupings based on their DNA patterns and their
genealogy. The
following table is an example from my Estes surname project which has very
successfully identified the various sons of our immigrant ancestor, Abraham
Estes. Based on his descendent
lines’ DNA, we have even successfully reconstructed what Abraham’s DNA
looked like so we have a firm basis for comparison.
Mutations are highlighted in yellow (will show grey in black and white). I
have shown only an example of the full chart below.
Moses through John R’s line does have line marker mutations on markers
that are not shown here. Elisha’s
line matches Abraham’s exactly. We
have had 4 descendents test from various sons of Elisha and so far we have found
no mutations.
What
Else Can We Tell? The
results of your tests not only tell you about your genealogy, they can also tell
you about your deep ancestry, known as genetic anthropology, and identify your
deep ancestral clan. Have
you ever wondered where your ancestors came from before contemporary times? We know that for the most part surnames did not exist before
1066, and in some places did not exist until much later.
The likelihood of us ever knowing where our ancestors were prior to 1066,
unless we are extremely lucky, is very remote using conventional genealogical
research methods. However,
now with the results of our DNA, we can peer through that window. Based on the results of our tests, and the relative rarity of
the combined numbers, humans are grouped together in clans.
We know who was a member of which clan by both the tests shown above and
a different kind of test, called a SNP (pronounced snip) test.
Population
geneticists are now using this information to determine how groups of people
migrated, and when. We may well be
able to tell if our clan is Celtic, or Viking, or related to Genghis Khan.
Based on our clan type, we may be able to tell where our group resided
during the last ice age, and then trace their path from there to England or
America over hundreds or thousands of years.
While this sounds farfetched, it certainly isn’t and many people are
discovering their deep ancestry. For
example, we know that the Estes clan wintered the last ice age in Anatolia, and
we know this because that is where other people who have this very rare
combination are found in greater numbers than anyplace else on earth. What
Does This Mean For My Family? It’s
easy to get started. You only need
one male volunteer that carries your last name who is descended from your oldest
progenitor by the same name and has a relatively firm genealogy. To
form a baseline within a family, we always eventually test two individuals from
two separate lines of the common ancestor, just in case an undocumented adoption
has occurred. If these two
individuals match, except for minor mutations, then we know basically what the
DNA of your ancestor will resemble and others can then test against that
established line. To
test mitochondrial DNA, you simply need to track a direct female line forward in
time from any female ancestor. To
test your own mitochondrial DNA, just test, and then look back on your pedigree
chart directly up your maternal branch of the tree (your mother, her mother, her
mother, etc.) to see whose mitochondrial DNA you carry. Project
Goals If
you are starting a DNA surname project, you will need to set some project goals.
Here are some common examples or goals reflecting what can be discovered
about genealogy from surname projects:
Does
Testing Hurt? Testing
is done using a cheek swab that looks like a Q-tip.
A test kit is shown below.
Just
swab the inside of your cheek, put the swab back in the vial and mail back to
the lab. I use Family Tree DNA to
coordinate my projects. You can
visit their web site at www.familytreedna.com
and enter your various family surnames to see if there are already surname
projects for your various ancestral lines.
You may be surprised to find that many of your ancestors are already
represented. Family
Tree DNA has been wonderful to work with, sponsors free surname and geographic
projects and are infinitely patient and extremely helpful.
To
see just an “average guy” collecting a sample from receiving the envelope in
the mail to mailing it off again, click here http://www.davedorsey.com/dna.html.
Scholarships If
you’re a female and can’t test for y-line markers, you’re not left out.
You’ll need to use traditional genealogy to find male lineal
descendents of your ancestor that carry the family name.
Then consider offering a scholarship for a descendent of that line to be
tested. Setting
Up Your Project!!!! I
hope that this article has whetted your appetite and made you curious.
You can be a pioneer with the same pioneering spirit that lived within
our ancestors as they ventured into uncharted lands. The secrets of our DNA are just waiting to be unlocked. To
see a project that is already set up and underway, you can go to http://www.familytreedna.com/public/Estes/.
This basic web space is provided for surname projects free by Family Tree
DNA, the testing company I have selected for the surname projects I manage, and
the good news is that you just type your info into a page - no programming
necessary. Benefits such as this
web site are some of the reasons why I selected Family Tree DNA, a decision
I’ve never regretted. An excellent privately created web page can be seen at http://small-stuff.com/MOORE/. To
see if your family name already has a project, visit www.familytreedna.com
and enter the last name into the search box located at the top of the page on
the right hand side. Receiving
your Results After
you receive your results, please consider our Y-Line or Mitochondrial DNA
Analysis packages at www.dnaexplain.com.
Family Tree DNA customers who have tested at 37 markers for the Y-line or
the mtDNAPlus for mitochondrial can order their reports directly from Family
Tree DNA on their personal page. What
you find in your own DNA will be priceless.
Begin your adventure today! Happy
hunting!!! Roberta
Estes
Copyright
2004-2009, DNAeXplain, all rights reserved.
|
Contact Information: Electronic mail General
Information/Project Membership:
[email protected]
NoticeThe Lost Colony Research Group is in NO WAY affiliated
with The Lost Colony Center for Science and Research. The Lost Colony Y-DNA and MT-DNA projects at Family Tree DNA are
NOT IN ANY
WAY affiliated with The Lost Colony Center for Science and Research,
"Please
notify us of any claims to the contrary." There is no fee to join our group and no donation of monies or objects are needed to participate in "The Lost Colony Research Group". ~~~~~~~~~~~~~~~ As with any DNA project, individuals pay for their own DNA testing, but the ~~~~~~~~~~~~~~~ Neither Rootsweb.com, myself, nor the Lost Colony Research Group together or individually are responsible for the personal content submitted by any individual to this website.
Send mail to [email protected] with
questions or comments about this web site.
|