The descendant of Cornelius Dorsey is a 25/25 marker match with John Dorsey of MD/WV.  Upgraded tests to Family Tree DNA’s third set of markers show these two to be a 35/37 marker match—still consistent with shared a close common ancestor.  Results for those markers are in Table I-2.  The two mismatching markers are shaded in blue.  Both of these markers have been chosen by Family Tree DNA because their relative volatility makes them potentially useful in identifying branching points of closely related lines.  Consequently, this difference is not surprising and may even prove useful as these two lines try to piece together the details of their relationship.

Line 12, Table I-1 presents 25 marker results for a descendant of a John Dorsey from County Clare in Ireland who has no known connection to Edward Darcy/Dorsey.  This John Dorsey, according to his grave marker, was born in 1828 in County Clare Ireland.¹⁰ He immigrated to Boston in 1856 and eventually to an Irish settlement in Refugio, Texas.  He has no known connection to the Edward Darcy/Dorsey line but is a 23/25 marker match with the descendants of John of MD/WV and Cornelius MD/SC and with another participant who is Irish born, and with the descendant of another John Dorsey from County Clare (Line 13, Table I-1).   He has one mutation at DYS458, that he does not share with anyone else in Lineage I—suggesting it is a fairly recent mutation in his line.  His second difference from the modal haplotype of Lineage I is a value of 17 at DYS464c. This mutation he shares with the last member of the group who was born and lives in Ireland.

Line 13, Table I-1 results are for a descendant of Patrick Darcy, who was born in 1846 in Bonavilla, a part of the townland of Ballymackea Beg in County Clare Ireland, to John Darcy and Honora Mungovan.¹¹  Patrick Darcy migrated to Washington Territory USA in 1881,¹² where he married Margaret Darcy,¹³ also from Bonavilla.  Her parents were Patrick Darcy and Eliza Looney.¹⁴ He matches the descendants of John Dorsey (MD > WV), Cornelius Dorsey, and John Dorsey (b. 1828, County Clare) at all markers except DYS391 for which he has the unusual value of 12.

Finally, the last member of this group is Irish born and lives in Ireland. His great-grandfather Thomas Darcy died in 1884 in Miltown, Solohead in County Limerick, near the Tipperary border.¹⁵  He is a 23/25 marker match with the John MD/WV and Cornelius MD/SC descendants, a 22/25 marker match with the descendant of John Darcy (1820) County Clare and as pointed out above a 12/12 match with the descendant of John Dorsey (b. 1828, County Clare).   All three participants with proven Irish origins share the same  values for DYS385b and DYS389i as the descendants of John MD/WV and Cornelius.  Those five differ at those markers from the descendants of ²Edward and ²John (of ¹Edward) Dorsey who share identical (and somewhat more unusual) values.   

The last line of Table I-1 presents a modal haplotype for Lineage I based on the most frequent value of each marker in the group.  (It should also be noted that at this time, the makeup of this group is biased toward descendants of Edward Darcy/Dorsey making the modal values weighted toward the Edward Darcy-Dorsey ancestral haplotype.) At one time, it was assumed that the common ancestor of this lineage would be the Immigrant Edward Darcy/Dorsey. However, with new data from participants whose Irish roots post-date the appearance of Edward Darcy/Dorsey in America, it would appear that this line will eventually be extended back to a common ancestor of Irish birth.  The results strongly suggest that Edward Darcy/Dorsey was also of Irish origin. 

Figure I-1 illustrates some of the ways the members of Lineage I might fit together in light of proven lineages, proposed lineages based on some traditional genealogical data, and DNA results.  Solid lines represent documented relationships reported by individual project members and dotted lines represent possible relationships that could be consistent with what we know from traditional records and DNA results.  (Naturally not all dotted line relationships can be true and I have undoubtedly missed some possible scenarios.)

Yellow boxes represent DNA project participants whose results place them in Lineage I.  All participants share the same values for 21 of the markers tested (see chart at the top of the diagram) which most likely represent unchanged values handed down from the common ancestor of all participants from this group.  Values for markers that are not shared by all Lineage I participants are given in their boxes for convenient identification of mutations. 

Figure I-1   Possible Dorsey lines and connections suggested by traditional genealogical records and DNA results.

Because of its size and complexity, Figure I-1a will obviously need to be enlarged to be read.  Two options are available below.

1)   John Dorsey of MD/WV and Cornelius Dorsey were not direct descendants of ¹Edward Darcy/Dorsey but rather shared a common ancestor with him and with the three participants with documented Irish roots.  Mutations at DYS389i and DYS385b occurred between that common ancestor and ¹Edward (most likely as the values that distinguish the ¹Edward Darcy/Dorsey line are the more unusual values for those markers) or between that common ancestor and a mutual common ancestor of the other American and Irish participants. A mutation at DYS455 has occurred in a later generation of ¹Edward’s line, possibly twice with parallel mutations in the lines of both of ¹Edward's sons ²Edward and ²John.  At least two mutations have occurred at DYS449 as four proven ¹Edward Darcy/Dorsey descendants have three different values for that marker. The easiest speculation is that the ancestral value of that marker was 30 and one line (²John/ ¹Edward) had a mutation involving a loss of one repeat and the other (²Edward/¹Edward) had a gain of a repeat.  Complicated as it is, this is the most probable and most parsimonious explanation of these results.

2) ²John and ²Edward were identical twins with two mutations occurring during the meiosis that produced the sperm that contributed their Y chromosome(s).  Parallel mutations at DYS455 have occurred in both lines as above.  At least three mutations occurred at DYS449—two in the descendents of Edward Darcy/Dorsey.  John MD/WV and Cornelius are descendants of Edward's third son ²Joshua who inherited the ancestral values unchanged from his father ¹Edward.  The Irish participants share a common ancestor with Edward Darcy/Dorsey.  This is very complicated as well as improbable.

3)   John WV and Cornelius share a common ancestor who was a descendant of ¹Edward Dorsey/Darcy (perhaps through his son ²Joshua as speculated).  Mutations at DYS389ii and DYS385b occurred during transmission events somewhere between ¹Edward and the common ancestor.  Coincidental identical mutations occurred in the Irish line.  This is very improbable.

4)   The three Irish participants are descendants of a son(s) ¹Edward left behind in Ireland (and ²Edward and ²John were identical twins) as per idea #2.

I welcome other ideas of explanations that are consistent with what is known.

Lineage I Matches with Other Surnames

Partial matches with other surnames are most likely indicative of a shared common ancestor before the advent of surnames and are of little value for genealogy.  However, as the number of matching markers increases, particularly those that include unusual marker values, it is prudent to review possible connections between families of those names who have been reported to be at the same place at the same time in family or public records.

There are opportunities for “non-paternal events” in every age, i.e., widows remarry and bring children, sometimes unborn, who take their stepfather’s names; parents die by accident, disease or war and relatives or friends takes in the children and raise them with their name; or a young daughter has a child out of wedlock and her parents raise it as their own. Infidelities within marriage occur—sometimes with and sometimes without the husband’s knowledge.  A widow may give her illegitimate child the name of her deceased husband.  A variety of scenarios over several generations could be devised to account for matches between individuals with different surnames.

Within the Family Tree DNA customer database of about 51,120  individuals (as of January 2, 2006), the descendants of ²John Dorsey only match each other at all 25 markers tested.¹⁶  They do match a few individuals of other surnames at 24/25 markers.  Some of those names are McClanahan, Parton, Cope, Raines and Cain which have (at least to my current knowledge) no obvious connections with the Dorsey family.

Of curious interest, there are also three 24/25 marker matches (a mismatch of one step at DYS385b) with individuals of the surname Wyatt.¹⁷ Table I-3 compares the proposed ancestral haplotype of ¹Edward Darcy/Dorsey with that of a matching Wyatt line. It is interesting to note that the Wyatts’ value of 13 at DYS385b makes their haplotype a bridge or intermediate haplotype between the descendants of ¹Edward Darcy-Dorsey and the rest of Lineage I.

These Wiatt/Wyatts trace their lines to Samuel Wiatt who was in Greenbriar County, Virginia (now West Virginia) in 1786, then moved first to Greene County, TN and then to Knox County, KY by 1805.  He died in July/Aug 1835.¹⁸   It is well known that ¹Edward Darcy/Dorsey and Nicholas Wyatt were both in Lower Norfolk County, Virginia in the 1640’s and moved to adjacent lands in Anne Arundel, County Maryland in the 1650’s.¹⁹  In fact, ¹Edward Darcy/Dorsey’s son ²Edward married Sarah, the daughter of Nicholas Wyatt.²⁰