The “Lobban” motif

The Lowland Lobban STR “motif” predates surnames

Most of the Y-DNA data mentioned on this website are from the “Big Y” tests (Y-500, later Y-700), which analyze single nucleotide polymorphisms (SNPs), the more useful for connecting family lines. But the tests from Y-37 to Y-111, which are short tandem repeat (STR) tests, also provide useful information. Jim Logan in the Clan Logan International Society has used them to work out all the “Limbs” in the Logan tree, as he explained in a seminar to the Society (recording accessible on the Society site, copy the password on the landing page ). The composition of Limbs 3 and 7 which you see on this One-Name site are Jim’s groupings, and I recently learned from our Y-DNA expert, John Sloan, that the Lowland Lobbans have a recognizable “motif” in the Y-111 STR results, i.e., a pattern of some unusual variations. The following brief explanation is based on what I understand from John and Jim. I will preface the description of the motif with a very brief primer on STRs, with the recommendation that if you want a more extensive explanation, you should watch Jim’s presentation.

STRs

The double helix structure of DNA consists of two linked strings of nucleotides, basically four: adenine, thymine, guanine and cytosine, usually just called A, T, G. and C. In the helix, A only pairs with T and C with G. In the small fragments of the 59-million base chain of the Y chromosome that are analyzed, one finds places where a short sequence of bases is repeated, e.g. GATA-GATA-GATA.

Example of single tandem repeats. Source: http://www.stewartsociety.org/images/bannockburn-tandem-repeats.jpg.

The number of repeats can change from generation to generation, and the analyses shown on the colored diagrams in FTDNA projects such as the Logan DNA Project, are matrices of the numbers of repeats at a certain segment (marker), for each participant along with the mode. Those that differs from the mode up or down are color coded.

The Lowland Lobban motif

To understand the motif, we first need to see that within the U198 project there is a set of haplogroups under DF89. The diagram below is one I adapted from the U198 site when we had only two Y700 results in Limb 7. Within the U198 data set is a subset defined as “DF89+ but FGC12305 negative” which I have outlined in red on the diagram.

“DF89+ but FGC12305 negative” subset within the DF89 subclade of U198. Adapted from a chart by John Sloan on the U198 Project website.

There are several markers that signal the Lobban motif but I first pick as an illustration one called DYS568 (chart below, extracted from the spreadsheet). Within this subset, most people have 11 repeats, that is the mode, but the minimum is 8 and maximum 12. All of the Limb 7 (JFS0275) members have 8 repeats, and there are two others, both in JFS0266, who also have that number.

Some of the subset “DF89+ but negative for FGC12305” showing some of the participants and one of the STR markers, DYS568. Screenshot snippets assembled from U198 Project colorized chart, https://www.familytreedna.com/public/U198/default.aspx?section=ycolorized

FTDNA explains the color coding: “The Y-Chromosome DNA (Y-DNA) results chart is color coded to show where someone in a subgroup differs from the calculated modal value for an STR (short tandem repeat) marker. For each step less than the modal value, a progressively darker shade of blue is used for the background color. For each step greater than the modal value, a progressively darker shade of pink is used for the background color.” Thus the strong blue shading indicates a value much lower than the modal.

The spreadsheet screenshot below collects just the Limb 7 people, along with Taffe and Bogard for comparison, and just the most important markers in the motif. DYS391 = 10; DYS449 = 30; DYS464 contains a 14; DYS456 = 14; DYS413 = 23, 24; DYS568 = 8.

The Lowland Lobban motif. In the header row, the STR markers coded with a red background are those that have faster mutation rates and are more likely to change within the genealogical time frame (FTDNA notes). In the data rows I had to adapt the coloring in making the spreadsheet. Source of data: U198 colorized chart for Y-111, https://www.familytreedna.com/public/U198/default.aspx?section=ycolorized

This pattern can be also recognized in some members of Limb 7 whose names are quite different from Lobban/Loban/Laban/Logan, who have tested no further than Y111. Updated results in the FTDNA tree show  that this motif dates back before surnames, and that JFS0275 split before surnames into at least two groups, the Lowland Lobbans, now identified by a more specific marker, JFS0277, and a new Holmes line that descends separately within the JFS0275 haplogroup. I have revised the Lowland Lobbans chart on the home page (Executive Summary)  to show these changes and also updated  the Status Report page and posted an updated  Y-DNA Report.

A new level of ancestors and their descendant families

What is really exciting about the motif, and the fact that the Holmes results have pushed JFS0275 back before surnames, is that the we now have a tool to explore another level of ancestry, the ancestors of our 1450AD MRCA, or at least the constellation of families among their descendants. There are other names in Limb 7 — Hemphill, Scarborough, and Nash, and the two Nashes have also upgraded to Y700 and show up in a branch above JFS0275, as shown below. I anticipate that the others will connect somewhere in this cluster over the Lowland Lobbans. I have yet to find out whether the Nashes have the motif, or something like it.  Finding out will tell us how near completion the motif was by the time of JFS0279. Taafe, one step further back at JFS0282 has two differences from the Lobban motif, so the motif could be recognizable in JFS0279 but not in JFS0282.

Haplogroups above the Lowland Lobbans, showing two other families indicated by Limb 7 donors.

 

Page created by Christopher S. Lobban based on information from John Sloan and Jim Logan, posted 7 Nov. 2021, revised 30 Nov.