For each short tandem repeat (STR) marker tested, the number shown in the table embedded below is the individual's value for that marker. |
Differences from the modal values for the family's haplogroup are color-coded; see the legend.
The markers that persist in a given family, differing from their haplogroup's modal values, are that family's CHARACTERISTIC MARKERS.
Characteristic markers can be used to combine the lineages of related testees into family groups and subgroups, and to separate unrelated lineages, by simple visual observation.
The DNA results tell us that:
In the table below, the family-specific markers are indicated by a colored vertical column within a family group, showing similar color shades and similar marker values.
(Differences between markers that are in the "Fast" mutation class can be discounted somewhat, since we are more likely to see mutations in them. This class includes 458, 449, 456, 576, 570, CDYa/b, and 534.)
[Use the scroll bars at bottom and at right of the table]
The identification of the groups shown on this page is one of the major goals of this project. The proof of the existence of five independent Thrift lineages (two within the same US state), and the demonstration that two geographically separated Thrift families have a common ancestor before 1650, shows the power of this technique. Similar groupings could be shown for the other surnames IF more people were tested.|
It is also possible to investigate, for each of these families, close matches to individuals with other surnames. Most such close matches indicate a relationship from before the establishment of surnames (which in England was circa 1300 AD). In a few cases, close matches with other surnames can provide clues about more recent events.
For more discussion of the closest matches of Firths to other surnames, see Firth Family grouping -(but this is now outdated).
An individual's collection of tested marker values is termed his haplotype. The similar-sounding term haplogroup refers to an identified group of individuals who share roughly similar haplotypes, not by accident, but because they have all descended from a common ancestor, usually in prehistoric times. (An approximation of that ancestor's haplotype can be inferred by finding the modal (most common) haplotype for the haplogroup, although this proxy ignores effects of complications such as genetic drift and sampling bias.) While a testee's haplogroup can often be predicted (guessed) based on the presence of characteristic STR marker values in his haplotype, this is not always reliable. In practice, haplogroups are confirmed by testing for a different type of marker (a single nucleotide polymorphism, or SNP) shared by everyone in the haplogroup.
Haplogroups are often referred to by groups of alternating letters and numbers, such as R1b1b1 or R1b1b2, intended to convey some idea of the relationships between groups and subgroups. However such names change often as new discoveries are made, which cause our understanding of the relationships between the subgroups to change. The haplogroup names that were in use in 2010 are in many cases outdated in 2011, and it is sometimes hard to know whether you are looking at a current haplogroup name or an outdated one. In fact since the official haplogroup-naming body is currently about 3 years out-of-date (http://ycc.biosci.arizona.edu/ ), the name used for a given subclade depends on which unofficial refererence is being used as a guide. See for example http://dgmweb.net/DNA/SNPcharts/R1b_current.html . A different convention is to refer to the major haplogroup and the most specific tested SNP; thus the subclade that FTDNA last year called R1b1b2 and this year calls R1b1a2 can be referred to as R-M269, and I2b2 is I-L38. I have not yet made these web pages self-consistent as far as naming haplogroups and subclades.
Haplogroup I2b, (identified by the SNP M436 or equivalent) has at least two subclades. The subclade I2b2 is identified by the SNP L38 (or the equivalent SNP L39), however it can usually be predicted by inspection of STR values, with characteristic markers DYS455 = 10, DYS454 = 12, and YCAa/b = 19/19. Haplogroup R1b1b2 (identified by the SNP M269) can be predicted by inspection of STR values, but its subclade R1b1b2a1a2f (identified by the SNP L21) is difficult to differentiate from R1b1b2 based on STR values. The Hampshire, England & northern Virginia, USA Frith/Thrifts have been tested and found positive for L21, but the other R1b1b2 families here have not yet been tested.SNPs are much more reliable markers for haplogroups than STRs because they mutate much more slowly, so duplicate SNPs occurring in different haplogroups are rare. On the other hand, STRs are useful in family studies precisely because they mutate so quickly (due to their repetitive structure); family branches which occur within a genealogically relevant time frame can be differentiated by STRs but generally not by SNPs. The average mutation rate for the STR markers is very roughly 1 per marker per 300 generations; if a whole set of 67 markers is monitored, this predicts roughly one change will be detected per 5 father/son transmissions, on average. In practice it can happen far more often, or far less often, than this. It is possible to find 6th cousins who have identical haplotypes, or a father and son who differ by two markers.
Closely related individuals will have almost identical STR marker values. The problem is that many 'unrelated' people in the same haplogroup will share most of the same marker values (because they do in fact share a common ancestor -it's just that the Most Recent Common Ancestor (MRCA) for the whole haplogroup was thousands of years earlier), so we have to be able to tell the difference between being closely related (that is, within "genealogical time") vs. just being in the same haplogroup.
To do this in a qualitative way, we
1) Note the modal (most common) marker values for the relevant haplogroup or subgroup;
This process helps us find the most likely relationships by visualizing patterns in the data; we can crudely rank the more probable vs. less probable explanations of the limited data available. (A closely related mathematical treatment addressing off-modal markers is Ken Nordtvedt's "More Realistic TMRCA Calculations".) This qualitative approach works well for the obvious cases, not so well for the borderline cases, as in more distant non-surname matches. (In this qualitative approach we are implicitly relying on the fact that sharing a surname is an independent factor which increases the odds that two haplotypes of a given haplogroup are related. Lack of a shared surname decreases those odds, thus more care is needed when investigating non-surname matches.) The best way to make a valid interpretation for the borderline cases is to get more data, since we are dealing with statistics. Always, the way to make our interpretations of the data fit reality better is to get more data -test more people, test more markers, and extend the documentation of the family trees. And there will be cases where the real explanation is not the statistically most likely one.Characteristic markers for descendants of:
Thrift of Hampshire, England, and Frith/Thrift of northern Virginia, USA: DYS439=11, DYS448=18, DYS460=10, YCAIIa=17, CDYa=38, DYS413b=24. DYS576=17 is a characteristic marker for the Virginia, USA branch, but may not be characteristic for the British Columbia, Canada /Hampshire, England branch.
Thrift, presumed of southern Virginia, USA: DYS390=23, DYS385a/b=14/15, DYS439=13, DYS458=19-20, DYS456=14, DYS570=18, CDYb=37, DYS438=13, DYS450=14, DYS520=19, DYS568=12.
Frith of South Carolina, USA: DYS390=25, DYS385b=15 [others would be identifiable if we had another 67-marker haplotype].
Robert T. Thrift of Georgia, USA: DYS390=23, DYS385b=13, DYS426=11, DYS388=15 [others would be identifiable if we had another 67-marker haplotype].
Firth of West Yorkshire, England: DYS393 = 14, DYS19=15, DYS458=18/19, DYS459b=9, DYS447=25, DYS449=29, Y-GATA-H4=8, DYS607=13, DYS576=15/16, CDYa=35, DYS557=14, and DYS617=14. [Some of these may be specific to the branches represented by the current testees.]
NOTE -These characteristic marker values use the current FTDNA convention. For comparisons against Ancestry.com or other databases, values for four specific markers need to be converted to Ancestry.com format. To the FTDNA value of DYS441 add 1; to DYS442 add 5; to Y-GATA-A10 add 2; and to Y-GATA-H4 add 1.
I'm trying out a new format for showing an Excel table on a web page. I hope it shows up well on your particular combination of browser & monitor.
Please let me know of any problems: Richard Thrift, rtx at cox dot net (please include "DNA Project" in the Email subject line).
(It may be difficult to read the STR marker names in the table, because of the small font used to allow more columns to be visible at once. Usually the marker names don't need to be legible; when desired you can alter the zoom setting of your browser.)