Question 1: Why is Alexander Montgomery b abt 1305 Renfrewshire, Scotland the earliest probable Founder for J-Z35794?
Answer: Because Alexander is the direct paternal ancestor of a J-Z35794 man and he lived closest to the J-Z35794 earliest probable age based on STR and SNP age estimation tools. Peter Archdale, whose ancestor Nicholas Montgomery changed his name to Archdall, is one of only 45 men in the world who have tested positive for J-Z35794 so far. His upgrade to the Y700 test defined the J-Z35794 to be the "Montgomery of Scotland SNP." His traditional genealogy records confirm Scottish Montgomery ancestry to Robert de Montgomery, founder of Clan Montgomery who was born in Renfrewshire, Scotland about 1125 CE. Peter Archdale's STR and SNP results link the man Alexander Montgomery b abt 1305 Renfrewshire, Scotland to be the earliest Probable Founder of J-Z35794 Haplogroup.
A. Record Evidence: Peter Archdale is the only man positive for J-Z35794 whose lineage has strong documentation back to the 12th Century. For details see his pedigree at WikiTree.
B. DNA Evidence: Per The Genealogist's Guide to Y-DNA Testing for Genetic Genealogy (Vance, 2020, Chapter 16), either SNPs or STRs can be used to estimate the time to a most recent common ancestor. STR methodologies include the Time Predictor Tool (TiP) at FTDNA for individual comparison between 2 testers and tools such as Still Another Phylogeny Program (SAPP) for more precise estimates with larger numbers of testers. Vance recommends YFull Haplotree estimates as the best SNP methodology rather than a simple formula multiplying the number of SNPs in a block of the FTDNA haplotree by an average age for all SNPs. YFull is the better method because it accounts for varying mutation rates in different regions of the Y chromosome, and is more specific to the location of each SNP.
STR Method Result using the TiP Tool: Using the TiP and accounting for known ancestors through traditional research as recommended by Vance, the 17 testers in the project with 111 markers were found to have one who did not match Archdale and 16 who have a 95% probability that their Most Recent Common Ancestor with Peter is between 10 and 15 generations back. Peter's ancestor 10 generations back is James Montgomery b abt 1544 and his ancestor 15 generations back is Robert "1st of Braidstane" Montgomerie b abt 1440. My next step is to see what the SAPP Tool tells us.
SNP Method using YFull and SNP Tracker Tool: YFull's method to date SNPs gives the age of J-Z35794 as "about 1410 CE, give or take 100 years." YFull provides more precise dates for STRs and is based on testers who have transferred their YDNA results to the company. I do not know how many testers in the project participate in YFull, but since the SNP Tracker tool at Scaled Innovation is based on the YFull date estimate for Haplogroups, I consulted the genius behind the SNP Tracker, Rob Spencer. He clarified for me that the SNP Tracker age for J-Z35794 of "52% chance with a confidence level of 95% of 2100 years before the present or approximately 180 BCE" translates to YFull's "about 1410 CE, give or take 100 years." Peter's ancestor living in 1310 CE is Alexander Montgomery b abt 1305 Renfrewshire, Scotland. His ancestor living in 1510 was Adam "4th of Braidstane" Montgomery b abt 1466. Per the SNP method of finding the probable earliest and most recent common ancestors.
In summary, these are the direct paternal ancestors of Peter Archdale with the earliest and latest probable dates for the Founder based on the STR and SNP dating methods used:
Alexander b abt 1305 Renfrewshire, Scotland Earliest Probable Founder of J-Z35794 based on SNP dating (ancestor living in 1310 CE), father of:
Sir John "9th Lord of Eaglesham" Montgomery b abt 1338 Renfrewshire, Scotland, father of:
Sir John Montgomery b abt 1362 Androssan, Ayrshire, Scotland, father of:
Alexander Montgomerie b abt 1413 in Scotland, father of:
Robert "1st of Braidstane" Montgomerie b abt 1440, Earliest Probable Founder based on STRs (15 generations before Peter), father of
Adam "4th of Braidstane" Montgomery b abt 1466, Most Recent Probable Founder of J-Z35794 based on SNP dating (ancestor living in 1510 CE), father of
Adam John "5th of Braidstane" Montgomerie b abt 1515, father of
James Montgomery b 1540s, Most Recent Probable Founder based on STRs (11 generations before Peter)
Note to Project Members: Check the TiP to see your comparison with Peter Archdale. Make sure you enter the number of generations you have confidence you do not share a common ancestor based on your traditional genealogy research and change the setting from "every 4 generations" to "every generation" for the most precise reading. Consider upgrading to Y700 if you have not yet. You will either match Peter's subclade, one of the other 5 subclades already identified, or create a new subclade if you match one of the men with J-Z35794 who have no match yet. Consider transferring your BigY results to YFull.
Question 2: Why is Jacob Nyberg in a category upstream from J-Z35794?
Answer: I decided not to limit my analysis to the 43 J-Z35794 men and their matches on Y and autosomal. If you go upstream from us 2 steps to J-Z35788, there are still only 69 men in the world who have that SNP and we are 43 of them. I think a broader look welcoming the other 26 men makes sense. The surnames for these 26 are Nyberg, Hunt, Wilson and Canning. It makes sense to keep an open mind and see what can be discovered by seeing all of us at WikiTree and under the same analysis umbrella.Question 3: What is Terri Stern's connection to the Montgomery Project?
Answer: My connection is to Agnes Montgomery b 1755, wife of Hugh Coffey, a Revolutionary War Patriot. I am getting strong indications from DNA that she is either the daughter or niece of Ninian Montgomery Sr who lived in Lancaster SC and that would be the Orange Group. It's my aunt's autosomal match to Nenion Montgomery Jr descendants triangulated with a descendant of Jane Montgomery St Lawrence that gave me the prediction that the Orange Group descends from Adam Montgomery 1540.