Double Cousins

I recently came across a report of a Dooley cousin in St. Louis - Alex Dooley, Hamburger Man in St. Louis - (though I haven't yet contacted this family and they may not be aware of our connection). My Legacy Family Tree software tells me that Alex's children are my fourth cousins, through two different paths, i.e., double fourth cousins.  I set out to find out what that means genetically and if there is some sort of metric to allow me to compare a "double fourth cousin" to the more common single fourth cousin.  There is a Coefficient of Relationship, R, related to degrees of relationship, but the math might be too much, so first I'll skip to the results, then try a brief basic explanation, then point to some resources for more information, if you're interested.


Single relationships

Siblings have about half of their genes in common, the degree of relationship is 1 or first, and the corresponding coefficient of relationship, R, is 1/2.  Advancing one generation: first cousins have in common about 1/8 of their genes, the degree of relationship is 3, and the corresponding R is 1/8. Each consecutive generation shares just 1/4 as many genes as the previous generation, the degree increases by 2, and the corresponding R is only 1/4 as large.  The following table shows these values through fourth cousins.

Relationship	Degree	R	% genes in common
Self or identical twins	0	1	100
Siblings	1	1/2	50
1st cousins	3	1/8	12.5
2nd cousins	5	1/32	3.1
3rd cousins	7	1/128	0.8
Double 4th cousins	8	1/256	0.4
4th cousins	9	1/512	0.2

Our double relationship

So, where does the "double" come in? Back in 1863, William Dooley married Elizabeth Martin in St. Louis.  In 1887, William's niece, Anastasia LaBrune, married Elizabeth's nephew, James Hogan. This created a double relationship between the Dooleys and the Hogans. William and Elizabeth's son, Thomas, was a first cousin to both Anastasia LaBrune on his father's side and James Hogan on his mother's side.  As an aside, since Thomas was an only child AND the Dooley's were Anastasia's only family in St. Louis AND Thomas and Anastasia were only four years apart in age AND James Hogan was also family AND the Hogan kids and Thomas' kids were all close in age, the Hogans and Dooleys were probably very close, akin to siblings, at least in their teen and adult lives.  In the next generation, Thomas' kids were second cousins to the Hogan kids, once through Anastasia and the Dooleys and again through James and the Martins.  This made them double second cousins. The next generation were then double third cousins, and so forth. How does that change the values in the table? Basically this means that instead of having one set of ancestors in common, they have two, both the same number of generations back, so the descendants of Thomas Dooley and of James and Anastasia LaBrune Hogan all have twice as many genes in common. The degree of relationship for double fourth cousins in 8, R is 1/256, and they have about 0.4% of their genes alike. According to one of the sources listed below, this is about 117 genes of the approximately 30,000 in the human genome.

More about quantifying relationships

If you'd like to know more, perhaps about how to include half siblings, or how to trace out any relationships, here are some explanations on the WWW:

Genetic and Quantitative Aspects of Genealogy
A thorough explanation of the Coefficient of Relationship (R) and related subjects.

Quantitative Consanguinity
A less through explanation with more applications to genealogy, but they only show degrees of relationship through 7, whereas a fourth cousin is degree 9.

Degrees of Relation and Number of Genes Shared
Not thorough, but relates R to the number of genes shared for various relationships.

Some Dooleys in St. Louis: Party and Recovery

Some e-mail I sent to family a few years back:


Hi, everyone.

It's a common goal in genealogy to trace your family history back just far enough to find a connection with the family tree of Charlemagne. I think that just about everyone with European ancestry is somehow tied to him, so if you can find the connection you can claim that you're related to royalty.

Well, here's the best I've come up with so far ...

Our Dooley ancestors came from Callan, Co. Kilkenny, Ireland to Dubuque, Iowa in the late 1830's. One branch of the family, the only that I know of with the name of Dooley, settled in Saint Louis around 1860. ... [Our parents] had Dooley 2nd cousins in St. Louis ... One of these Dooley cousins, Joseph, married Edmer Anheuser, a granddaughter to Eberhardt Anheuser, the original owner of what later became Anheuser Busch brewery. (By 1829, Joseph remarried, and I don't know what became of Edmer Anheuser.) So there's our link to American "royalty".


[Follow on e-mail:]


Hi, again.

This is so ironic, you may not believe it's true.

So, the other day I sent a message about how we're connected to Budweiser through Joseph Dooley, a cousin in St. Louis. Joseph had a twin brother, William, who married Cornelia Howe. Cornelia's father was the inventor of TUMS (the famous antacid)! William was the Secretary of Dr. Howe's company, the Lewis-Howe Company. So apparently the Dooleys were well prepared for both the party and the recovery.

Another interesting coincidence: The William & Cornelia Dooley house is now part of the Webster University campus (I think it houses the English Dept.). The Dooleys must have been living there when [private] went to school there (previously Webster College) in the early '40s. It was "The Dooley House" when the University bought it in about 1984, and has now been renamed Pearson house. The Howe house, next door, is now also owned by the University. These houses, and Webster U., are located in Webster Groves, near St. Louis.

Some Old St. Louis Photographs: Mr. & Mrs. Wm. Dooley

I came across some very old photographs recently.  Fortunately, two of them identified the subjects, relatives though not direct ancestors.  I'm trying to figure who these folks are.  All of the photos were taken in St. Louis, home of our Hogan ancestors and Dooley relatives.  Here's what I know so far.

 These first two are identified.  They are of Mr. and Mrs. William Dooley.  William Dooley was a successful grocer in St. Louis.  He immigrated in about 1850, and in 1863 married 25 year old Elizabeth Martin, also an Irish immigrant.  William Dooley was the brother of Catherine Dooley LaBrune, my great great grandmother.  Elizabeth Martin Dooley was the sister of Anastasia Martin Hogan, another great great grand-mother.  So they are not direct ancestors, but close relatives.

When were these photos taken?  Elizabeth died in 1881, so hers was taken earlier than that. Since they are no longer here to be offended by my guesses at their ages, my guess from the photos is that she was about 40 years old, and he 45.  From their dates of birth in 1838 and 1827, respectively, the photographs might have been taken in about 1878 and 1872.  Since the two photos are sequentially numbered, they were probably taken at the same time.

For more information, I googled  Scholten Photography in St. Louis and found two lists of historic photographers with helpful information. Early St. Louis Photographers lists photographers in St. Louis and their known dates of operation at given addresses. Their information places these photos between about 1863 and 1875. Langdon's List of 19th & Early 20th Century Photographers was not precise for these two photos.

Putting all of this information together, I'm guessing these photos were taken in about 1872, when Elizabeth and William were 34 and 45 years old, respectively.