Michael Cooley's Genetic Genealogy Blog GEN • GEN
26 September 2016

Big Y Results for Strother Group 01

This is my first introduction to the Strother DNA Project. I've been a co-admin for it for awhile, perhaps about two years. My job has primarily been to maintain the DNA results page, though most of my work has been on the Cooley DNA Project. (I maintain nine surname projects at Family Tree DNA.) STRs are easy to maintain. But now a member of Group 01 (kit #522183) has the results of his Big Y test. That's a different matter altogether and takes a great deal of thought — and explanation. First, a quick DNA tutorial.

Autosomes

We get about half of our DNA from each parent. Throughout our reproductive years, our bodies create germ cells, half of our genetic makeup, through a process called recombination. Because the process is random, each germ cell (sperm and egg) is unique. (Unique cells, after all, make unique individuals, the very reason we're not clones.) The chromosomes that go through recombination, chromosomes 1 through 22, have two "bases" — one from each parent. For example, the two bases on position 175522 of my sister's 6th chromosome are A and G -- one from Mom and one from Dad. There's no effective way to determine which base came from which parent except through comparing with the results of relatives. For example, I share the same mother with my siblings:


ChrPosition
Me19389873AG
Sister19389873AG
Half-sister19389873GG

Yet it's not that simple. Mom had two copies herself and could have passed either of the values to one child then another to the next. There's also the chance of random mutations that could cause a flip to another value. The only way to make this work is to compare clear across the spectrum. To do this, autosomal tests look at about 900,000 positions. The combined evidence becomes overwhelming.

Mitochondrial DNA

But there are two kinds of DNA that have only one base: the Y chromosome (Y-DNA), which is passed from father to son, and Mitochondrial DNA (mtDNA), passed from mother to all children. Here's a position on my mtDNA compared with my sisters. Without doubt, we know what my mother's mtDNA looked like. Aside from the occasional mutation, it can be no other way. With only one base, mtDNA does clone itself.


ChrPosition
MeMT16540C
SisterMT16540C
Half-sisterMT16540C

Surname DNA Projects

Surname DNA projects are not concerned with autosomes or mtDNA for the simple reason that the descent of the surname follows the male line, at least in our culture. In other words, names can piggyback, so to speak, on the Y chromosome, which has only one base and, therefore, has nothing with which to recombine. If a man has a particular base having the value of T, in all likelihood so did his father, his father, and his father, going back generations. Of course, nothing is as easy as it first looks. There are two kinds of tests for the Y, STRs and SNPs:

Short Tandem Repeats (STRs)

STRs are much as they sound: short strings of genetic letters that repeat X number of times in tandem to another. For example, at a region called DYS449 I have 34 repeats of TTTC. There's nothing special about that. But these regions can be compared among testers. Those that closely match, especially if the same surname is involved, can be grouped together, as we've done in the Strother DNA Project. Grouped men probably have some degree of relationship, even if ancient. The problem with STRs is that these regions are highly volatile. Repeats can be added from one generation to the next and then subtracted in a following generation, ending up where it started. With the potential of the number of repeats at any particular position going up and down, it's nearly impossible to determine what might have happened. Nevertheless, it's a safe bet that those STRs shared among members of a large group likely belonged to its most recent common ancestor (MRCA). For example, Group 01 has an interesting marker at DYS449, the same I just wrote about. The first two entries have 30 repeats of TTTC at that location. Kit number 111286 has 27 repeats. The rest, including those with known descent from William Strother (died 1702), have 27 repeats. Because of the problematic nature of STRs, we can't know for sure what that might mean, but it's a curious note. Indeed, I have found such a marker in the Cooley CF01 group that has proven to be significant.

Single Nucleotide Polymorphisms (SNPs)

SNPs are a different matter. Here we look at only the single base, or nucleotide, at any position. These values, as I stated above, can change for only one reason — mutation. Such an event is called a single nucleotide polymorphism. On average, we're each born with about 60 such mutations — a very slight number considering that our DNA is comprised of about 3.1 billion nucleotide pairs (base pairs). Of those, the Y chromosome, puny as it in fact is, has only about 37 million bases. SNP mutations on the Y are rare. But as the chromosome passes from one generation to the next, from father to son, these mutations accumulate. In our Y, we each have an archive of all the changes that occurred in our paternal line going back tens, even hundreds, of thousands of years. The more SNPs we share with one another, the closer we're related. Two people who match completely are very closely related — father / son, brothers, cousins, uncle / nephew, etc. In fact, I share all but about a half dozen mutations with a 5th cousin once removed. The greater that number, the older the MRCA.

The Big Y

Ten million of the 37 million bases on the Y chromosome are examined for this test, about 27 percent of the Y. This is a substantial number with which we can make accurate determinations. In fact, ten million might be approaching the usable limit. There are areas that can't be effectively looked at: areas that resemble the X chromosome, regions of STRs, the tips of the Y which frequently touch and exchange genetic data with the X, the coding regions where genes are found, those areas in which all human males will match anyway, and areas that simply can't be reliably read or haven't been accurately mapped. Still, ten million bases are more than adequate.

The objective is simple: find those SNPs that mismatch among testers. (The vast, nearly uncountable majority do match across the species.) That number is initially quite large, but as the number of comparisons rise, unmatched SNPs begin to break up into groups parsed along newly-found MRCAs, such as the one below. Although a second Group 01 Strother has yet to test, we're lucky in that there's a reasonable match with a Simpson tester:



Earlier Big Y testing discovered ZP70, Simpson's presently documented terminal SNP. But the new test has found a new terminal SNP, yet to be named (see article 24). Before this test, Simpson had at least 27 unmatched SNPs — the 12 he shares with the Strother family and the 15 that are now deemed his "private" SNPS, those that are not yet known to belong to anyone else.

Interpretation

What does this tell us about the Strother family? Firstly, the group shares a very old MRCA with Simpson. How old we can only guess at for now. Secondly, all Group 01 Strothers share at least some of the private SNPs now known to belong to our tester. The older the relationship between two men, the fewer shared SNPs we'll find in that block. Indeed, the block of SNPs is so old that any number of non-Strothers testers will cause the block to split from about middle and above.

As it is, Group 01 has quite a genetic tree now. We've known for as long as the group has existed that its members possess the SNP dubbed M269, one of the defining SNPs of haplogroup R1b. But M269 may be as old at 13,500 years, its MRCA going back at least 7300 years ago. It's a huge jump from that to the 17th century when William was born. For now, we know the following descent:


M269 → L150 → L23 → L51 → L151 → P311 → P312 →
L21 → DF49 → ZP20 → ZP21 → ZZ33_1 → ZP23 →
ZP70 → MRCA → unknown families →
unknown Strother MRCA → tester

There are a lot of unknowns here. All of this may seem purely academic, but keep in mind that each and everyone of these SNPs were born right along with (and inside) specific men. The man born more than 20,000 years ago having M269 might have been called Ugh, but we now know him as M269. Large gaps exist, but a number of them will be filled in the next years and decades with newly discovered SNPs.

I have found no solid guesstimate about the age of ZP70, but considering that SNPs appear to emerge, on average, about one per every 144 years (I happen to know that my four private SNPs were born about every 46 years), ZP70 is likely 3,000 to 4,000 years old. The Strother / Simpson MRCA might be about 2,500 years old. Indeed, anyway we break it down, we have a long way to go. If members continue to SNP test, we'll one day find SNPs that represent men inside the genealogical timeframe and the SNP tree will merge with the Strother lineage. My own Cooley lineage has nearly done so, and will once I find the appropriate testers in England. Through a combination of SNP testing and old-fashioned genealogical research, the Strothers will finally nail it down.

Geography

SNPs not only represent men but whole populations founded by the original SNP bearer, and that means that populations represent specific geographic regions. For example, I can trace my origins from the Caucasus Mountains through Eastern Europe, Scandinavia, Scotland, England, and finally to the American colonies. SNPs, then, are about time and space. Not quite in the Einsteinian sense, of course, but certainly in an archaeological sense.

Next Steps

Since William Strother is a known entity and is shared among several members, his descendants would be a good starting point for further analysis. Those SNPs a second tester shares with the current tester will be the SNPs that their MRCA was born with. The SNPs that any two William Strother descendants share will be the SNPs that William, the MRCA, was born with. So, the more the block is broken down, the better we can determine the general relationship between group members and the more accurately developed will the tree be, even if the exact nodes (and names) are yet to be discovered.

I created the above graphic using FTDNA's initial reports. It's entirely preliminary; more work to be done. The tester's raw data, called a BAM file, will be sent to YFull.com for further analysis. (Their results will come in long before FTDNA's analysis arrives.) And I've submitted the new Strother private SNPs to yseq.net for further investigation and naming. Once the whole thing is done, all new, viable SNPs will have names, some may have been removed as being unreliable, and others may be discovered in the raw data. (YFull's criteria is somewhat more liberal than FTDNA's, but as valid nonetheless.)

My Struthers

This is a good time to share the fact that I have a Struthers descent, as below, a decidedly Scots-Irish lineage:


William Struthers (1757-1834) m Janet Lindsay
James Struthers (1793-1871) m Elizabeth Saville
Martha Jane Struthers (1823-1854) m John A Foster
Nancy J Foster (1853-1916) m Robert I Hogue
Hugh W Hogue (1894-1969) m Birdie N McDowell
Billie Hogue (1931-1995) m Jack Cooley
Michael Cooley (1950-)

William took his family to Virginia in 1797. He's believed to be the William born 5 Jun 1757 in Avondale, Lanarkshire, Scotland. If so, he resembles this entry from Group 01. Might William and James have been brothers?


Kit #86531: James Struthers b. 1760 and Janet Lindsey

Project Funds

The project currently has $75 in funds. I'd like to suggest that it be used to offset the cost of our next Big Y, which is otherwise $575! Since we have a head start for Group 01, a member of that group will be given preference. The results will greatly enhance the work already done. Anyone wishing to contribute may do so through this link: Donations. And note that FTDNA generally offers a Big Y sale over the holidays, usually a $100 discount.


Any thoughts, concerns, questions? Please feel free to contact me via the link below.