Project Criteria for Genealogical Significance
The overall criterion for declaring a genealogically significant match
within Taylor Family Genes is this:
Y-DNA indicates a high probability of
sharing a common male ancestor who lived since 1350 AD*.
This plain-English statement relates the DNA evidence to genealogy and is
then translated into quantitative criteria, based on the number of markers
compared and the number which agree (or the genetic distance):
- High probability means equal to or greater than 80%.
- The year 1350 AD represents the usual earliest beginning of the
Genealogic Time Frame in
England, a time period for which it is possible to identify
ancestors by name, date, place and other characteristics. For specific
families, the genealogic time frame may extend further into the past.
For others, it may be more recent.
- It has been approximately 660 years since 1350. At an average generation length of
27.5 years, this is about 24 generations.
What matches qualify under this criteria?
- 12 markers -- None qualify. Even for a 0:12 match (no genetic distance),
the CMA may be thousands of years in the past.
- 25 markers -- => 0:25, equivalent to a genetic distance of 0 or less for
25 markers, If higher-level comparisons (37, 67 or 111 markers) are
available, they will be used instead.
- 37 markers -- => 4:37, equivalent to a genetic distance of 4 or less for
37 markers; or, a TiP score of >= 80% for 24 generations.
- 67 markers -- => 7:67, equivalent to a genetic distance of 7 for
67 markers ; or, a TiP score of >= 80% for 24 generations.
- 111 markers -- We have not yet developed a standard for 111 markers.
Suggestions are that it is <=10:111. We also use a TiP score of >= 80% for
Please note that, by employing the TIP algorithm, these criteria are less restrictive than those used by
FTDNA to report matches within its total database, nor are they
dependent on surnames matching. Also note that they
are more restrictive than past project criteria; some older groups were
formed under looser criteria but have not been "revoked". We
encourage those with 12- and 25-marker matches to upgrade their testing
levels in order to benefit from the higher precision of the 37-marker
and 67-marker tests.