DNA Testing your DESCENDENTS with BIG Y 700--Part 2

 

Earlier this year I published a post that is part 1 of this post. In that I described testing my grandson and a couple of questions it raised.

1. Did the one mutated ySTR between me and my grandson occur when my son was conceived or when my grandson was conceived?
2. Will my son's terminal ySNP cover my grandson's "private variant" or is that variant the unique marker for my grandson? 

Now my son's test results are back and I have the answers to those questions and more! 

1. My son and I are 111/111 marker exact ySTR matches so my grandson is the mutant. The mutation between me and my grandson that I reported in my previous post was formed when my grandson was conceived.
   
2. My son's terminal ySNP does cover my grandson's "private variant". As of now neither of them are shown to have any private variants.

More exciting to me is that my son and grandson share a terminal ySNP, R-FTC50269, that I do not share. It appears to have been formed when my son was conceived in 1969. All patrilineal descendants of my son--and therefore of me--will forever carry this ySNP. FTDNA's new beta version of their Discovery tool illustrates this ySNP:

 

 

Your Y-DNA Haplogroup Report for R-FTC50269

The Y chromosome is passed on from father to son, remaining mostly unaltered from generation to generation, except for small trackable changes from time to time. By comparing these small differences in high-coverage test results, we can reconstruct a large Family Tree of Mankind where all Y chromosomes go back to a single common ancestor who lived hundreds of thousands of years ago. This tree allows us to explore paternal lineages through time and place and to uncover the modern history of your direct paternal surname line and the ancient history of your ancestors.

 

R-FTC50269

Haplogroup R-FTC50269 represents a man who is estimated to have been born around 50 years ago, plus or minus 100 years.

That corresponds to about 2000 CE with a 95% probability he was born between 1885 and 1998 CE.

R-FTC50269's paternal lineage branched off from R-FGC43697 and the rest of mankind about 100 years ago, plus or minus 50 years.

He is the most recent paternal line ancestor of all members of this group.

There are 2 DNA test-confirmed descendants, and they have specified that their direct paternal origins are from United States.

As more people test, the history of this genetic lineage might be further refined.

 

For more information about this ySNP click here.

 

 

It looks like testing the younger generation has given me a genetic coat of arms!

 

 

DNA Testing your descendants with BIG Y

 

Those of us who are veterans of atDNA testing have long preached "test the oldest generation of the family." For atDNA testing this is still great advice. However, there may be times when we can learn from testing the youngest generation.

I know that there are various schools of thought about how old a child should be before they are tested. That topic is an important one which I will not deal with here. I have long tested family members of all ages. By so doing I discovered several years ago that grandchildren do not inherit exactly one-fourth of their atDNA from each grandparent. You can see my blog post about that (I got it wrong).

More recently I bought a BIG Y 700 test for my oldest grandson. Until now ySTR tests have primarily been to find matches among other test-takers. ySNP tests have been primarily to discover new branching points along the Y chromosome since possibly sixteen million or more locations can be explored. As his results have come back, I have so far learned two things: 

1. Either my grandson or his father is a "mutant." My grandson matches me on 110 of the first 111 markers over which FTDNA tests ySTRs. In one of the two conception events a mismatch occurred. 
2. Prior to my grandson's test results, I had two "private variants" not found in the genome of any man previously tested. Now both of those variants are shown in the box with the white background in the column on the left below. Now that two men have had those ySNPs show up in their tests, they have become "named SNPs" and added to the BIG Y Tree, In addition my grandson's test results had identified a new "private variant" which had not previously been discovered.    
   

 

So what if anything have I learned about my family history by testing my grandson? In the test of his first 111 ySTR markers, we had one mismatch. This allows FTDNA's YDNA TiP tool to predict that we have a 78% chance of sharing a common patrilineal ancestor within 2 generations. (The correct answer.) The TiP tool predicts we have a 95 percent chance of sharing that common ancestor within 4 generations. He is not my closest match over the first 111 ySTR markers. I have one cousin who is an exact match over those markers. However, that cousin shares 6 Big Y STR differences with me when all 590 STRs tested are considered. My grandson shares only 2 STR differences with me over all STRs 659 tested. Since ySTRs can mutate at random, when more are tested the results are more accurate. The results confirm that he is in fact probably relate to me within two generations along my patrilineal line.

The two ySNPs in the white box above, R-FGC43697 and R-FGC43683 are equivalent SNPs for genealogical purposes at least for now. We really can't tell which occurred first. What these designations tell us is that these SNPs are part of the R1b male haplogroup and they are #43,683 and #43,697 of the ySNPs discovered by and named by the Full Genome Corporation lab. Other than that these numbers have no significance. For now my grandson and I are the only two men who have mutations at these locations. We would expect any of our male descendants to inherit them. They would become a sort of genetic signature of our particular family line of descent--our genetic coat of arms. Early indications are that these mutations may have occurred about a hundred years ago. More testing by family members will be needed to learn more specifically when they may first have occurred. Below is a timeline chart generated by Rob Spencer's Tracking Back tools:

This suggests that ySNP R-FGC43697 may have been created by a mutation in a birth event occurring around the beginning of the 20th century. Also note that my previous haplogroup assignment of FGC43694 as well as other nearby cousins like all of us under ySNP R-BY2666 appear to be connecting back as far as 1,500 years ago. Several SNPs back then have yet to be separated out time wise.  

The results of my grandson's test have pushed my own terminal ySNP down into genealogical time--perhaps to the last two or three generations. This has caused us to order a BIG Y 700 test for my son. That may be overkill. I would have considered it to be a few months ago. However, it will show us a couple of things at the very least.

1. Did the one mutated ySTR between me and my grandson occur when my son was conceived or when my grandson was conceived?
2. Will my son's terminal ySNP cover my grandson's "private variant" or is that variant the unique marker for my grandson?
   

It is an expensive way to add these two bits of information to our family history but I could plan a genealogical research trip that could cost more that the test with less guarantee of new information.

SAVE THE DATE: Requires advanced registration

FREE WEBINAR From SCGS, Saturday, May 2, 2020 at 10:00 AM Pacific

 

When Prussian Grandpa Contributed 
No DNA, Can We Find Out Who Did?

Free Webinar from SCGS

Saturday, May 2, 2020,
10:00 AM (Pacific Time)

Register here:

https://attendee.gotowebinar.com/register/5494035707154445314

ABOUT THE PRESENTATION

When three siblings did not receive any DNA from their supposed maternal grandfather, a systematic research plan traced the origin of the biological grandfather. Family oral histories, digital phasing, DNA testing of many extended family members and analysis of xDNA inheritance patterns were needed to find the real source of that missing DNA. It was from Donaghadee, Ireland rather than Prussia.

ABOUT THE SPEAKER

David Dowell, PhD, was a librarian for 35 years and a special investigative officer in the USAF for 4 years and has two degrees in history and two in library science. He has researched family histories since the 1960s. His most recent books are NextGen Genealogy: The DNA Connection (2015) and Crash Course in Genealogy (2011). Previously he taught “Genealogy Research” and “Ethics in the Information Age” at Cuesta College and chaired the Genealogy Committee and the Ethics Committee of the American Library Association. He blogs as “Dr. D Digs Up Ancestors” at http://blog.ddowell.com and coordinates three DNA projects.

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Webinars are archived and available only to SCGS members as a benefit of membership in the society. The webinar archive can be found at http://www.scgsgenealogy.com/webinar/archive-index.html.

"SNPS still hurt my head"

My cousin wrote "SNPS still hurt my head. Have not spent enough time with them." This is not my high school dropout cousin emailing. This is my PhD research chemist cousin who travels the globe to attend scientific conferences to share findings with fellow cancer researchers. If ySNPs still hurt your head too, you are in good company. 


What the heck are ySTRs?

This is a cousin who long since had tested his ySTRs to 111 markers. He and I match on 110 of 111 ySTR markers. My 5th great-grandfather, Peter Dowell, Sr. (1714-1802), is his 6th great-grandfather. Well maybe this is an opportunity to let him spend some more time wrapping his mind around ySNPs. Maybe, in so doing, I can begin to relieve some of his head pain. Maybe.

All of you who have used census records can relate to how data on ySTRs (short tandem repeats on the Y chromosome) are collected and compared. The locations visited for 12, 25, 37, 67 or 111 ySTR marker tests are not magical. They were picked originally because geneticists knew how to repeatedly and reliably locate them. Also they were thought to mutate just fast enough to be useful for genealogists. That means they are relatively stable for several generations so that men who share enough of them probably share a common patrilineal ancestor in genealogical times. At they same time they mutate frequently enough to differentiate between distinctly different lines of ancestors.

To use a simple example, let us assume that you know there is a village that has either 12, 25, 37, 67 or 111 distinct residences. You send a census taker to visit each residence and determine how many ySTRs reside at each location. In the lab this is what geneticists are doing when they collect data for ySTR comparisons. They sample the number of ySTRs "residing" on the Y chromosomes of men to give us an idea of whether or not those men are closely related. How many generations ago could a common patrilineal ancestor of those men have lived if the two men might be expected to have accumulated the number of variations that are observed in the current test results?

RECONSTRUCTING THE FOUNDER’S 111-MARKER DNA SIGNATURE

[from David R. Dowell, NextGen Genealogy: The DNA Connection, (2015), pp. 33-4.] 

Surname projects can apply these principles to reconstruct more complex descendant trees of family “founders.” In this case the “founder” was Philip Dowell, who appeared in the records of southern Maryland in the 1690s. By that time he was an established tobacco planter. His marriage in 1702 and death in 1733 are well documented, as are many other events in his adult life. However, no birth or christening records have yet been discovered. Although he is reported to have had four sons who passed his Y-chromosome DNA forward, living male Dowell descendants of only three of those sons have been identified and tested.

Five of those descendants have tested to 111 Y-STR markers. One was a descendant of Philip’s first son, one was a descendant of Philip’s second son, and three were descendants of Philip’s third son. The results of these tests were that all five agreed on 101 of the 111 markers. In addition, four of the five (including descendants of at least two of Philip’s sons) shared the same value on all 111 markers. In other words, none of the two mutations of the descendant of the eldest son, the six mutations of the second son, or the single mutations of two descendants of the third son occurred on the same marker. Philip can be assumed to have passed down the marker values that at least four of his five living descendants share because they were passed down through multiple lines that have no common ancestor more recent than him.

Triangulating 111 ySTR markers back to the founder of the Maryland Dowells                       

Since this chart was prepared another Dowell has tested who is a 111/111 match for the reconstructed yDNA signature for the Founder. However, we are still in the process of determining this man's exact line of descent.


What the heck are ySNPs?

While ySTR analysis has helped the Maryland Dowells understand much about their inter-relationships in North America, it has yet to connect them with specific ancestors across the pond. Could ySNP (Single Nucleotide Polymorphisms located along the y-chromosome) analysis help?

As noted above ySTR analysis is all about determining whether or not men share the same number of repeats at predetermined locations along their yDNA. In other words do they match. ySNP analysis can also be at that level as well. If a man is fortunate enough to have a supposed relative who has already been SNP tested, a test of individual ySNPs can be a cost effective method of way to validate a match and also a ySNP for that man. 

However, for the most part, ySNP analysis is a voyage of discovery along the approximately fifty-eight million locations of one's y-chromosome. We can now get reliable readings on almost one fourth of those locations. When testing for SNPs we do not target a certain number of predefined and well known locations. We travel down our chromosome and look for branching points. These are  points where closely related genomes permanently separate -- somewhat akin to taking an exit off the Interstate. Most of the group continue on unchanged on the main genetic highway but one branches off and passes this branching point "mutation" on to all his descendants. So far Family Tree DNA (FTDNA) has identified more than 408,000 such branching points (ySNPs) in the yDNA samples the company has tested. Additional SNPs are discovered with almost every BIG Y test conducted.  

These SNPs trace the paths our genomes have traveled through prehistory and down to the present. Now that more and more men have tested to this level it is beginning to be possible to see branching points in genealogical times when we had surnames and some paper records exist. Thanks to the work of Alex Williamson with his Big Tree of the major haplogroup found along the Atlantic Coast of Europe, we can begin compare SNP branching with the STR and paper trail documentation we have seen in previous decades. Comparing Alex's SNP tree with the one seen above, three branches emerge that help refine the genetic trails of Philip Dowell's three sons that had been put together from paper documents and STR data. 

For the purist this charting process reversed the chronological order of the sons. In this chart the descendant of eldest son is on the right and the descendants of the third son on the left. However, the main take away for today is that branching SNPs have been discovered that separate the lines of descent within the last three centuries. The eagle-eye readers will note that a fellow traveler of a different surname has joined the genetic migration. His family was associated by both location and business transactions in both Maryland and North Carolina. The SNP branching suggests the genomic link is with the second son although other evidence is more ambiguous. 

Is you head hurting even more now?