CASH v. LETITIA
DNA testing  Cashel with the Letitia branch.
For background see
DNA testing for the Blennerhassett problem.
This page is about the tests done to prove or disprove the
Theory of our descent from Letitia Blennerhassett of Tarbert.
The results (below) say that the Letitia theory is not true.
We are not closely related to
Letitia Blennerhassett of Tarbert.
Groups
We compare individuals from the
groups defined here.
This page will compare:
We start by considering total segment matches, using minimum segment size = 9 cM.
9 cM is generally considered significant.
We compare our family
with the Letitia Blennerhassett family.
 This looks really bad.
 We have done
one to one comparisons.
And we only
scrape in with a single match just on the boundary of 9 cM.
 Also, the match is not where it should be.
The theory says we are closest to REV.
But the borderline match is in ED.

Compare this with the
9 cM table
for the Baronets theory
(which is well populated).
 There is also a borderline
8.6 cM
match with REV,
which would round up to 9 cM.
But this hardly changes our analysis.
The best match for the Letitia theory
is this 9.0 cM match of
ED.4 and CASH.16.
ED.4 is in the Clifford line,
descended from
Mary Blennerhassett, sister of Rev. John.
CASH.16 is a descendant of
Blennerhassett Cashel.
This is only a borderline match.
Let us try (as some sites do)
reducing the minimum segment size and looking at total segment matches.
Here is total segment matches using minimum segment size = 7 cM.
Matches for CASH with LETITIA emerge:
 With this metric (minimum segment 7 cM), more borderline matches emerge,
including some with REV.
 But the matches are not hugely convincing.
Compare this with the
7 cM table
for the Baronets theory.
 We have done a lot of samples to get such weak matches.
 The Letitia theory predicts stronger matches with REV than with ED.
And this is not what we see here.
We now take a wider look at the data by showing for every match, what is the largest segment.
Largest single segment in match, in cM.
Small segments can happen by chance. Large segments much less so.
 CASH borderline matches REV and ED.
 Our Letitia theory predicts much stronger matches with REV than with ED, though.
And this is not what we see here.
If there is a segment over 5 cM,
Gedmatch
estimates the number of generations to Most Recent Common Ancestor (MRCA).
This is an estimate from the DNA, not from the family tree.
Gedmatch can give different estimates depending on the minimum segment length you pick.
We use the closest estimate, which is the estimate given under minimum segment 5 cM.
 The CASH link to ED seems stronger under this metric.
 But the segment lengths are weak.
 And it matches in ED not REV.
The Letitia theory predicts a closer relationship with REV, and we do not see that.
Now we consider, under the Letitia theory, the
postulated
cousin relations of CASH with REV and ED.
If
George Cashel
is the son of
Letitia Blennerhassett of Tarbert,
then these would be the postulated cousin relations:
Here are the Gedmatch estimated MRCAs:
There is no match with the postulated cousins.
The Letitia theory looks false.
Here are the largest segments:
There is no match with the postulated cousins.
The Letitia theory looks false.
Let us write out the entire list of results for
real cousins
versus the same list for
postulated cousins,
separate into lists for each type of cousin,
and sort the lists,
to see if the postulated has the same pattern as the real.
This is where the Letitia theory really looks false.
The below shows that for we should already have got some great hits for CASH.
We should have a bunch of strong "blue" hits already. But we have basically nothing.
The Letitia theory is false.
Here are the lists, for each type of cousin,
of largest segments
for real cousins
versus the same list for
postulated cousins (for CASH crossed with REV and ED).
We start at "4.0" cousins (there are no closer living postulated cousins).

The Letitia theory is false.

4.0 and 4.1 cousins should have much stronger matches.

I got all the 4th cousins:
When I started the DNA testing, the closest of all living relations of the two sides (according to my theory of cousin relationship)
were 4th cousins no times removed (4.0).
Two living on my side.
Three living on the Letitia side.

After much work,
I managed to get all 5 samples,
and could do all 6 comparisons.
This, of all places, was where the theory should have been proved.
And nothing matched at all.
The Letitia theory is false.
The Letitia theory looks false.
5.0 and 5.1 cousins should have much stronger matches.
 Our only match shows up here. It is for two 6th cousins.
 The Letitia theory still looks false though.
We have enough samples now to declare that the Letitia theory looks
false.
 We have some borderline matches of CASH with ED and REV.
 We finally got a 9 cM, but only after hundreds of comparisons.
And only one.
And it is in ED.
It should be in REV.
 If you look at the MRCA, CASH seems to match ED.
 However the good MRCA result is in the wrong place.
It should be in REV.

If we look at
all of our matches
the pattern is very random, and strongly suggests
the Letitia theory is false.
 The total failure of 4th cousin matches strongly suggests
the Letitia theory is false.