Jackson Brigade DNA Project

Jackson Brigade, Inc.

Jackson Brigade DNA Project

At the end of October, 2011, the Jackson Brigade's Board approved of the Jackson Brigade DNA Project with the following goals:

To establish a base of DNA knowledge for others to compare to.
To find cousins to whom we could reach out and invite to become members of Jackson Brigade.
To gather DNA evidence to aid in proving family connections of interest to the Jackson Brigade.

The DNA Project's Recent Activities

After the project's approval, Board members identified two males with Jackson surnames who we were confident (by research and written documents) are descendants of John Jackson and Elizabeth Cummins. In November, 2011, the two (Board members John M. Jackson and Robert Lee Jackson) took Y-DNA67 tests through the Jackson Surname Group of the company Family Tree DNA. The funds to pay for the testing were raised by special donations.
The Jackson Group of Family Tree DNA has a web site at http://www.familytreedna.com/public/Jackson/
By the end of January, 2012, John and Lee had received the initial results of the Y-DNA67 tests. Everyone agreed that interpreting the results was daunting! We agreed to work on unraveling the jargon jungle and to study up on DNA testing in the summer, 2012, when many of us had more free time.
In July, 2012, after reading and investigating many hours on DNA testing, Dan Hyde decided he had enough details to create this Jackson Brigade DNA Project web page.

Background on Y-DNA Testing

Those who had high school biology will remember that humans have 23 pairs of chromosomes (for a total of 46 chromosomes). The chromosome pair designated 23 is special and determines the sex of the individual. When forming the chromosome pair 23, if the individual receives an X chromosome from the mother and an X chromosome from the father, the individual is female (XX). If the individual receives an X chromosome from the mother and a Y chromosome from the father, the individual is male (XY). The Y chromosome is passed from the father to the son virtually unchanged.

The Y in Y-DNA testing refers to the Y chromosome passed from a father to a son. The reason Y-DNA testing is especially useful for genealogy is that the Y chromosome is passed intact from father to son down through the generations in the same way surnames are passed in most cultures. Here is a Descendant Chart that shows how male A passes on his Y-chromosome.

In the above Descendant Chart for ancestor A, he passes on his Y-chromosome to the males designated in dark blue squares. Note that it's common to represent the males by squares and the females by circles. For the males B and C, male A is the most recent common ancestor (MRCA). If males B and C both took Y-DNA tests, their results would show a close match. Therefore, a family history researcher could conclude that the two are closely related through a MRCA.

Image of Pedigree Chart for Henry J. Jackson, Jr.

The above diagram is a Pedigree Chart for Henry J. Jackson, Jr. that shows his parents and grandparents. In a Pedigree Chart, the top most person in each column is a father that passed on his Y-chromosome to his son all the way to down to the further most person on the left (assuming the person is male). These individuals have been colored in blue in the diagram and are referred to as the "Y-Chromosome Line." Notice that Y-DNA testing is only useful for direct male lineal descent (father to son to grandson, etc.), i.e., the blue colored boxees. It says nothing about the many descendants through the female lines.

For example, going back five generations, you have in your Pedigree Chart 64 ancestors (2 parents, 4 grandparents, 8 great grandparents, 16 great-great grandparents and 32 great-great-great grandparents) assuming no cross marriages such as with two first cousins marrying. Assuming you are male, Y-DNA testing only supplies information about the five direct male ancestors (your father, his father, his father, etc.) along the Y-Chromosome Line (the blue boxes in the above Pedigree Chart). A Y-DNA test says nothing about the other 59 ancestors!

However, even with this severe limitation, the Y-DNA test can be useful for genealogy. For example, a family history researcher could use it to determine if two branches of a surname share a common ancestor. The researcher just has to identify a male from each surname branch that descends through the male lineage back to the common ancestor. Most researchers would identify two males from each branch in case one individual might have a "hidden" adoption or an infidelity. Y-DNA tests deal with strictly male blood lines.

The "67" in the Y-DNA67 test refers to the number of markers used in the test. In genetic genealogy (the name for using genetics for genealogy), DNA labs use completely different markers from the ones used by the police at crime scenes as seen on CSI and the ones used by the medical profession for susceptibility to diseases. If one is considering a Y-DNA test, he need not worry about the police knocking on his door or about revealing health issues. Y-DNA tests specific markers on a male's Y-chromosome known as Short Tandom Repeat, or STR markers. The number of markers tested by most DNA testing companies can range from a minimum of 12 to as many as 111, with 67 being commonly considered a useful amount. Having additional markers tested will generally refine the predictive period in which two individuals are related, helpful for affirming or disproving a genealogical connection on the direct paternal line. Testing for more markers increases the cost. Testing for Y-DNA67 currently costs about $250 per individual; however, Family Tree DNA recently had a sale where they charged $200.

A second DNA Test for mtDNA

In the above Pedigree Chart, a pink arrow labeled mtDNA Line travels down from Henry J. Jackson, Jr. by the lowest female in each column (colored pink). Every individual (male and female) inherits his or her mother's Mitochondria, i.e., organelles outside the nucleus of the cell that converts food into energy for the cell to live. Males don't pass on their Mitochodria; only females. These Mitochodria have their own DNA (called mtDNA) different from the DNA in the 46 chromosomes inside the cell's nucleus. You can have your mtDNA tested at Family Tree DNA and other companies if you wish. It's a different test from a Y-DNA test with its own price (about $160). However, mtDNA testing is of limited use for family history. Scientists, especially anthropologists, use mtDNA to trace the migration patterns of people over thousands of years.

Other Resources

For more details on DNA testing visit Blair Genealogy's great web site: DNA 101

Results

Results are slim at the moment. We are just beginning this DNA project.

John and Lee's Y-DNA matched 66 markers out of the 67. This gives a 95% probability of a common ancestor in the last 8 generations. Since John descends from John and Elizabeth Jackson's son Henry and is 8 generations away and Lee descends from John and Elizabeth Jackson's son John Jr. and is 6 generations away, this makes sense. If you consider more generations, we have a 99% statistical probability of a connection sometime - anytime - within the last 12 generations.

From the two Y-DNA tests, we can determine the haplogroup for the John Jackson/Elizabeth Cummins line. It is a very common one (R1b1a2). A large percentage of Western Europe is in this haplogroup! One study determined 92.3% of the men in Wales and 85.4% of the men in Ireland are in this haplogroup. Another study states that in parts of north-western Ireland the R1b1a2 haplogroup reaches 98%. This seems to confirm that John Jackson was from Ireland.

Using Y-DNA to test your line against ours

Because the baseline shows a very common haplogroup, the matches at 12, 25, and even 37 are not reliable. It is a bit unfortunate, but to have a good match, the prospective match will probably need to test all 67 markers and perhaps even 111 markers.

We hope eventually the effort and money that went toward establishing our DNA baseline will work to others' advantage. We know a lot of folks want to believe they are related to Stonewall Jackson's line!! Now they have a way to verify that! But they will have to pay for the 67 marker test because the lower level tests just won't do the job for this common haplotype.

Please contact Dan Hyde (hyde at bucknell dot edu) if you are interested in comparing your Y-DNA tests with our baseline data.

Page maintained by Dan Hyde, hyde at bucknell.edu Last update July 31, 2012

No guarantee on the accuracy of the data found on this web site is given or implied by the site owner. As with all family research, the researcher should strive to obtain primary documents for necessary proofs. Furthermore, permission must be obtained from the original submitter of information on this site before publishing any information found here.