(R1b-BY24824)
Michael Cooley
The objectives of Y-DNA projects are essentially two-fold. First, to find genetic markers that will distinguish between the various lineages and, secondly, to obtain genetic data that will be useful in determining the family's origins.
An example of the first objective is found in the marker Y133702 (see "SNP Tree," second graphic below). Genetic research has demonstrated that it first emerged in Jeremiah Strother (1655-1741), a son of William Strother who is the Earliest Known Ancestor (EKA) for this lineage. William is currently represented by the BY23497 block of SNPs. Any male Strother descendant of Jeremiah's will have this marker. And, if the research is indeed correct, only Jeremiah descendants will be in possession of it. Likewise for Jeremiah's son, Francis Strother (1700-1741), and the marker A20343. His (and only his) male-lineage descendants are carrying a copy it every cell.
Y133702 and A20343 are what I call anchor SNPs. Their "births" have been narrowed down to the births of specific men at specific places and times. They're rare largely because the genealogical timeframe is narrow and because new Y markers generally arrive only every four generations or so. Unless an earlier ancestor is well-known to history and has had sufficient lines of progeny worked out, we're not likely to find many in the earlier timeframe. Still, we can narrow down to a broad geographical region and timeframe.
And that brings me to the second objective — origins. This can be accomplished by casting a wide net. The following Strother tree is bracketed by distantly-related families, the Struthers, Allisons, and Reids. Not only do they have Scottish origins, but provide genetic (and regional) context to the balance of the tree. In the end, we'd like to see a gentle blending of those blue boxes found in the graphic at the bottom of this page.
The following table is simply a bare summary of the results and can be copied and pasted into a spreadsheet. This is helpful for keeping track of larger projects. With the exception of those indicated by an asterisk, the novel SNPs (novel variants) can be tested at YSEQ.net for $18 each and a one-time kit fee of $6 for the first order.
| KIT | TREE | MRCA | TEST | NOVEL VARIANTS | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| #386246 | | BY188221
| #94368 | --
| #90562 | FTB66245
| #71892 | BY187132
| #169888 | --
| #581793 | FT25277
| #75847 | FT26831
| #608983 | FT287237 FT287848 FT287895 FT287921
| #Y-32011 | --
| #945703 | FTA28823 FTA28998 FTA34086 FTA27627
| #126422 | --
| #282558 | A23649 A22620 FT323585
| #83607 | FTB70502
| #33480 | A22909 FT134838 FT133239
| #YSEQ-5 | --
| #984342 | --
| #152639 | A24380
| #522183 | --
| #555347 | --
| #IN61230 | FT339063 FT339133 FT334153
| |
* SNP cannot undergo Sanger testing
A SNP (Single Nucleotide Polymorphism) occurs when there's a genetic change at a single position, for example an A mutated to a C. Each marker listed in the tree below is a SNP, and each one was manifested at the birth of a single man. This doesn't happen every generation but, if we had enough data, they'd all line up one after the other in a timeline. In other words, each of these markers is a direct representative of a specific man born at a specific time and place. For that reason, I like to say that "SNPs are people too." It's not literally true, of course, but conjures an image that is reasonably apropos.
Every marker above is a direct genetic representation of the first man born with that marker. However, each marker could represent three or four more men not born with a new, unique marker.
Count the number of markers upstream of any one kit. Then multiply that by four generations. I'll leave it to you detemine how many years makes a generation. This can be done for all kits descended from any one haplogroup. Average the grand total to get an average timeline for the haplogroup. The word "average" is, however, the key. The more participants, the more that number will change.
This is a simplified, barebones, stripped-down SNP Tree (as above). It's called a Quick Tree merely because it can be created once new results are downloaded. It has the advantage of allowing a tested group member to easily trace their SNP lineage.
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STRs (Short Tandem Repeats) are the markers found on the results page of every FTDNA project. They're completely different from SNPs. For example, the number in the first column for the following markers, labeled DYS393, is merely the count of the number of times the sequence AGAT is repeated in the tester's cells. More about the markers can be found on the Wikipedia page for List of Y-STR markers.
The top line in this graphic, in gray, is the modal value. It represents the most common value found among each tester. The total number of mismatches any one tester has to the modal is noted in blue parenthesis next to the tester's kit number. This number is referred to as the genetic distance or GD. For example, a tester might be a GD of 1 from the modal's CDYb marker but with a total GD of 5 from the modal as a whole.
Here we compare the genetic distance between each tester rather than to the modal. This gives us a better idea as to how closely the testers are related to one another as opposed each to the modal, or mutual ancestor. The results tend to clump together by haplogroup. However, due to the volatile nature of STRs, the clumping is often inconsistent, as shown by the same graphics in the somewhat larger YP4248 Subclade Project. For this reason, STRs are unreliable for phylogeny. Nevertheless, the study can help direct us toward those kits that could provide the greatest impact on the project for Big Y upgrades.
The color version results from replacing the numeric values with color values. This doesn't tell us much for small groups but can be informative for groups of ten and more.
