Humphrys genealogy

Genealogy research by Mark Humphrys.

Our family:

Main theory:


DNA testing for the Blennerhassett problem

The "Holy Grail" of my family tree was the Blennerhassett problem, the problem of figuring out how the Cashel family (our family) descends from the Blennerhassett family.

After years of gathering paper evidence, I turned to DNA.
In 2020, DNA finally proved we are descended from the Blennerhassett Baronets branch.

Stats:    DNA samples so far.    one-to-one DNA comparisons.

Note: In fact we are not checking some one-to-one comparisons, such as DAU versus LETITIA, since there is no point.
But we could do them later if we change our mind.


The general plan of DNA testing for the Blennerhassett problem

  1. Gather the DNA of as many descendants of George Cashel as possible.
  2. Target a specific branch of the Blennerhassetts where there is at least some paper evidence that they might be the branch we are related to.
  3. Gather the DNA of as many people in that branch as possible.
  4. Get their DNA on Gedmatch (where anyone can compare DNA with anyone).
  5. Do one-to-one Autosomal DNA comparison of everyone with everyone.
  6. Build up a map.
  7. See what the map says.

The groups

We divide our samples into groups.

CASH - Our family

DAU - Blennerhassett Baronets family

(The theory, based on some paper evidence, is that our ancestor comes from the Blennerhassett Baronets family. We named this group "DAU" since the family story is our ancestor was a Blennerhassett daughter. But this may not be true. We could come from a Blennerhassett son in this branch. So DAU is not a good name. We will change the name at some point.)

LETITIA - Letitia Blennerhassett branch

(The theory, based on some paper evidence, is that our ancestor is Letitia Blennerhassett of Tarbert.)

DISC - Disconnected Blennerhassett families


DAU versus LETITIA - too distant

We could consider comparing DAU with LETITIA.
Most (but not all) of them have Blennerhassett ancestry, and descend from a common Blennerhassett tree.
But the common ancestor is too far back. You have to go back to Capt. Robert Blennerhassett (born around 1620s).
So we are not going to compare them. There is no point.

Guide to results pages


Disproved - Letitia Blennerhassett of Tarbert

The first DNA project I did was to look at the family of Letitia Blennerhassett of Tarbert.

Proved - inside Blennerhassett and inside Cashel


Proved - Blennerhassett Baronets


Unproved - other Blennerhassett lines

Summary of findings


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