R-Z8 and the Tapscotts

The y (male) chromosome is the only nuclear chromosome that does not undergo recombination during reproduction (during “meiosis”). Thus, it gets passed down unscrambled from male to male. This being the case, one might expect the y chromosome to be identical for all males. Because of mutations, however, it isn’t. (For which geneticists are thankful.)

Two types of yDNA mutations are of interest to genetic genealogists—changes in the numbers of repeats in series of repeating units (short tandem repeats, STRs) and replacements of one nucleotide by another at particular positions in the DNA chain (single nucleotide polymorphisms, SNPs). STR testing is the common method used in yDNA genealogy analysis to show relationship between males, particularly those having the same surname. SNP testing, on the other hand, is used to determine a male’s haplogroup, which shows where he lies on the yDNA haplotree. It is possible to predict the y haplogroup from STR testing only but it is only a prediction. All male Tapscotts who have thus far undergone yDNA STR testing and have made their results known have a predicted haplogroup of R-M269, rather uninformative information considering that this is the dominant branch of the most frequently occurring y chromosome haplogroup in Western Europe. Pick anyone off a European street, and he is not unlikely to belong to haplogroup R-M269. What is needed is testing by selected male Tapscotts to confirm and refine their haplogroup. (Perhaps we should say "haplogroups" since a person in a particular haplogroup also belongs to haplogroups further up the branch of the yDNA haplotree.)

Two male Tapscotts have now undergone SNP testing, one descended from Edney (me) and one descended from Edney’s brother Capt. Henry. Both have confirmed haplogroups of R-Z8, a subgroup of R-M269 that branched off perhaps 2000 years ago from European Germanic tribes, arriving in the British Isles with the 5^th-century AD Germanic invasion (all this is still uncertain). The  sequence of haplogroups as one travels down the M269 branch is M269>L23>L51>U106>L48>Z9>Z30>Z2>Z7>Z8>Z11>Z12, with other haplogroups yet to be identified. It is likely that all Tapscotts descended by all-male lines from Henry the Immigrant of Virginia will be found as having Z8 as their haplogroup. Further testing would refine this further, showing location further down the haplotree branch. To do this I have ordered the R1b - Z8 SNP Pack test from FamilyTreeDNA.

Past postings (23 Oct 2013, 19 Mar 2014, 18 Jul 2014) have noted that y STR testing indicates a relationship between Tapscotts and some members of the Bowling (and related names) families. In 67-marker yDNA STR tests, distances of six steps or less are found in matches between Tapscotts and Bowlings with confirmed haplogroups of R-Z8, R-U106, and R-Z12. R-Z12 is a subgroup of R-Z8 and thus people belonging to the R-Z12 haplogroup automatically belong to R-Z8. R-U106 lies further up the branch from R-Z8 and people testing positive for R-Z8 will automatically belong to R-U106, though the reverse is not true.

If the matching Bowling family members do indeed have a male ancestor in common with the Virginia Tapscotts, the two families would have to possess the same haplogroup. Thus, the SNP test results described above reinforce the possibility of a common ancestor. Deeper ancestral testing may provide additional evidence for a linkage. Note, however, that SNP test results cannot prove a common recent ancestor, but they could rule out such an ancestor.