Understanding the SNP Testing Results of the M44/E1a1 Phelps of Caswell Co, NC, Albemarle Co, VA, and Baltimore Co, Md. - and POnd of Mecklenberg Co. VA
While yDNA STRs have been used for years to determine paternal surname groupings , they can be misleading or confusing for family branches. This has been is especially true with the lines from Caswell Co, NC; Albemarle Co VA; and Baltimore Co, Md. For a review of our past work, a summary table of the STRs at the FTDNA yDNA table is here: As you will see there, STRs have been of minimal little help in defining family branches.
While yDNA SNPs have traditionally been used to test for haplogroup definition they are far more reliable than STRs for testing family lines and branches. Practically speaking, SNP mutations can be considered to be once-in-a- lifetime and are inherited by all male descendants without change. Thus with appropriate SNP testing, a haplogroup or family branch can be determined by one or at most a few SNPs. . They are initially more expensive and are limited to approximately 140 year periods.
Here is a report on a successful genealogical use of SNPs: ADVANCED Y-DNA TESTINGFOR THE ACREE ONE-NAME STUDY
To uncover the SNP(s) that identify a historical lineage from the past down to the present, one must compare at least two men who are known to have a close STR genetic distance. The same surname is preferable, The comparison and SNP identification is based on a professional level analysis of full SNP tests, such as a Big Y test. SNPs are compared to find SNPs that are shared uniquely between them which indicates a common ancestor; and SNPs that are unique, novel and/or private to their own recent line or branch. It is then reasonable to approximate aging to their common ancestor. (With addiional tests, aging becomes more accurate. FTDNA.com and FULLGENOMES.com offer SNP testing. YFULL.com offers a professional analysis of those SNPs. They also provide a resulting SNP tree which includes family branches when two or more men are tested who meet the requirements.
The Phelps under study are of close genetic distances and are proven to be M44 E1a1. Full SNP testing was done by FTDNA and analyzed by Yfull.com.
By identifying the unique private snps for a given Phelps, others may then test simply for those snps. If the tested person has a known genealogical dated branch, the resulting unmatched snp(s) are those mutating before the branch. Our testing now provides for SNP testing for these Phelps major lines with branches becoming possible - even without any traditional STR testing. Some Phelps have already tested individual SNPs at YSEQ.com at $18 each. Package/panels prices are available for some. Some have tested at FTDNA at $39 each with the advantage of being viewable on their Project pages..
Always remember that without genealogy, yDNA SNPs cannot identify the ancestor, but with SNP testing can narrow your genealogy search to an approximate time and branch relative to others who have so tested. Thus SNP testing can build and extend on known genealogy The more who test the more detailed the results.
Once the results are in here is how we make use of them.
Ydna Triangulation of two men to their common ancestor allows us to deduce the ydna of that common ancestor
SNP for all practical purposes mutate once forever. And are always handed down father to son.. So by triangulating “up the tree” we can deduce the snps (and usually is STR markers althought they are not as reliable) of the common ancestor. Once we deduce his snps we can triangulate to even another common ancestor using another descendant branch.
Then we can assume those snps are in those who are geogelogically downstream in that lineage, but haven’t even been tested.
But if someone is outside the tree above, and the members have no positive snps or unique str values, we cant assume or deduce or triangulate anything. This is the case of a number of our members. The only answer is when a new snp is found to test it.. or for someone to be chosen to do a Big y test, hoping to find new individual snps to test.
But again, with no multiple sons to a target ancestor, we will only be able to assume or guess his snp or strs. For example, Because we have only one son of Felps of Baltimore we will never be able to triangulate to him. So we have to assume the oldest triangulalted snp was in Felps or earlier, but it could be it mutated after Felps. Thus the most recent new snp found in 331150 could have been before Felps… or after. I am assuming after, but since we are seeing maybe two snp mutations in a short time period in the 1700s, the oldest snp could have mutated before Felps. The general rule is snps mutate about every 144 years on the average