67-marker YDNA

DNA analysis offers a new approach to genealogy. Men get their Y chromosome from their fathers, and  – were it not for mutations  – all male descendants of a given male ancestor would have the same Y "markers." Although the mutations are unpredictable, they occur at a reasonably predictable rate. So, statistically, the degree of agreement between the Y chromosomes of two men says how far back their common ancestor was.

As of June 2012, roughly 500 male Montgomerys have had their DNA analyzed, and most have agreed to share the results in a surname project. Something like 140 of us have gone to 67 markers in the laboratory analysis. Except for kit# 31542, who used 37 markers, the following uses the 67 markers.

The organization of this report begins with the classic analysis based on genetic distance. Additional information (sometimes superior knowledge) is gained through what I call branching analysis. Branching analysis will be treated separately. Then I will get to general conclusions and discussion.

In addition, other DNA analysis leads to findings on "haplogroups." Although they do not help the immediate paper trail, I will report on these findings as a matter of some interest.

The results of my DNA 67-marker analysis show near matches that I would like to use. Though no one matches my DNA exactly on 67 markers, there are three other Montgomery males with "genetic distance" (g.d.) of 1 and 18 others with g.d. of 2 measured with respect to me. G.d. is essentially the number of mutations. [See the footnote.]

The table shows the testers with g.d. of 1.

G.d. Kit Most distant known ancestor
self35720John PA>NC 1773 d 1795 son Samuel b ? 1761 >TN
163925/71700Rev William b Cumberland PA 1768 >NC>GA d MS1848
1237807Alexander Montgomery, Sr., b 1728, County Monaghan, Ireland, and d 1810, Oswego, New York
1 on 3731542Elias b ? 1775 >NY d ? 1846

In this group, 63925 and 71700 are father and son. So we get no additional information on ancestry from that duplication; their most distant known is Rev. William Montgomery. For online elaboration about Rev. William, see Foote's book, Sketches of North Carolina, Historical and Biographical, Illustrative of the Principles of a Portion of Her Early Settlers.) Another with g.d. of 1 is 31542 (measured with just 37 markers), whose most distant known is Elias Montgomery, associated with New York. Neither of these lines goes back earlier than the time of my John; so it is hard to apply their paper trails to my work. I tried to use the Cumberland connection in searching for my John in Pennsylvania without success. The line leading back to County Monaghan, Ireland (237807) came to light during the past year. It is intriguing as it links to the New York connection. Unfortunately, the Elias line is Otsego Co., while the Alexander line is Oswego; they are about 120 miles apart.

FTDNA reports 18 men with g.d.=2. 17 of them have identical 67 markers. They are generally connected with the famous Houston line (identified by the couple married in Pennsylvania, John Montgomery and Esther Houston). The other is kit# 31550, whose most-distant known John died in SC in 1784 (a contemporary of my John). Four of these project participants have paper documentation going back earlier than do I, and all four believe their ancestor was from Ulster. Three of these have identified Antrim as the source.

The probability of my having an ancestor in common with any of these participants is affected by the knowledge that he existed before John; that is, he does not lie within 6 generations of me. The following table (generated with the Family Tree DNA calculator) shows the probability of having the common ancestor within N generations, using the observation that he is not within 6 generations.

N g.d.=1
(17 identical on 67)
8 73.5% 64.4%
12 96.0% 92.9%

For example, since my John is 6 generations back, there is a 73.5% probability that his grandfather (generation 8) is also in the line of those with g.d.=1 There seems to be a fair chance that my John was no more than 2 generations away from Ulster, possibly County Antrim or Monaghan.

More detail of the project and updated results are shown on the website, www.familytreedna.com/public/Montgomery/.

Analysis of the whole is complicated by test results of a male surnamed Ball appearing close to my results. See ball.htm.

A couple of results are enough to make the DNA work worth it to me: The analysis implies that, in my line, the father of record in all the generations back (surnamed Montgomery) was indeed the biological father. As a second significant note, there is a Montgomery line that ended up in Blount County, close to the Knox-County home of my Samuel (son of John), that I have been running across for years (identified by the couple, John Montgomery and Esther Houston). It has been tempting to say, as a number of well-meaning observers have said, there "must" be a close connection between Samuel and this line. At least two of the participants in the DNA analysis, however, claim to be in that line, and the chromosomes say that Samuel was not all that close: my g.d. from that line is 2.

Please read the section on branching analysis before proceeding.

Other than the few sequences described in the branching analysis, I do not believe we can identify the order of the mutations from the base of the "first Montgomery." In particular, the 17 value in column 55 (DYS534, discussed at length last year) could have occurred before or after the other mutations from the base.

The branching analysis provides the answer to the frequent question, "Why do two participants known to have family ties have a large g.d.?" Namely, the mutations occured after lines branched. With the diagram before you, look at two examples where the branching analysis provides insight. (1) Kits 35720 and 188794 show a difference on 67 markers of 3 steps, but 35720 branched from 188794. (2) Kits 62961 and 237807 differ in 4 markers, but they are known through paper research to have a common ancestor. The branching analysis found that each line came from 35720, independent of that paper research.

I tried to use the implications of the DNA work accordingly in the search for my John Montgomery. See that search regarding other John Montgomerys in particular. In the past, we spent much time with two families in which the husband was a John Montgomery; both lived in Pennsylvania during the same era, and at least one migrated to North Carolina.
    The first was John and Martha Finley (called by some JMMF). (This is the line of Clark B.) The significance of that couple is that there was a John in that JMMF family with virtually nothing known about him. From the little we know of ages, that son of the first John, would have been the right age to be my John. The branching analysis does not rule out this identification.
    The second family was John and (maiden name) Martha Montgomery (JMMM). (This is the line of Keith.) They lived close to my Montgomerys in North Carolina. However, the branching analysis puts this family in Group D, excluding their direct relationshhip to my John.

HAPLOGROUPS (General interest though not directly applicable)
Every male can be placed in a haplogroup. A haplogroup is a group of identical Y-chromosomes that share a very distant common ancestor in whom a particular mutation occurred. The mutation that defines group J2, in particular, is thought to have occurred in Mesopotamia about 18,500 years ago. The defining characteristics of each haplogroup mutate very rarely, and analysis over time and location of the characteristics in males allows the tracking of ancient migrations. The J2 group spread in all directions, including westward, from the "fertile crescent." In Europe today, J2 reaches its highest frequency in Greece. The frequency of J2 in the European population decreases as the sample moves north.

To bring us back to the Montgomery ancestry, the Montgomery name goes back to Roger de Montgomery (called "The Great") of Normandy. He was father to another Roger, born about 1030 who assisted William the Conqueror in the invasion of England in 1066. Analysis now concludes that these Montgomerys were in haplogroup J2.

The Montgomery Surname DNA Project has identified five different major haplogroups to date, with a handful of different haplogroups outside the five main groupings. Our surname has had plenty of opportunity to spread over the centuries since it first came into use. Beyond biological heritage, some Montgomerys got that surname through adoption of the surname (In England the adoption of a surname was not compulsory until the 13th century.), adoption of children, and illegitimacy.

The remarkable point is that FamilyTreeDNA confirms me as being in haplogroup J2. So despite historic opportunities to the contrary, I am a biological descendent of the "original" Montgomery family of Normandy.

Footnote: To first approximation, genetic distance is the number of makers that are different, but if certain pairs of markers - known to change at the same time - differ, the pair counts as only one in calculating g.d. In comparing my markers with the latter 17 participants, there are three differences. The mismatch on two markers, however, counts as only one since they are not independent. That is, these 17 participants have a "genetic distance" of 2, not 3.

Revised July 7, 2012
In addition to the possibility of typos, it remains possible that I have made logical errors. I will welcome questions and corrections.
David Carey Montgomery

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