DAU

DNA testing - inside the Blennerhassett Baronets branch.
For background see DNA testing for the Blennerhassett problem.

This page is about the tests done to prove our descent from the Blennerhassett Baronets branch, looking at the theory of a lost daughter of this branch.

As part of the testing, we proved some lines inside the known (or believed) Blennerhassett Baronets tree.

Groups

We compare individuals from the groups defined here.

This page will compare:

DAU v DAU

Proven (or believed) cousins

First, we lay out the known cousin relationships (known from the family tree) of people inside this branch.
Then we can compare DNA results to their known cousin relationship.

BART 1, 2 and 3 are a tightly related group. BART 7 is close to them.
The other BART are spread out.
We need more BART samples.
BUTLER is part of YIELD.
- BUTLER are now proved to be part of YIELD. The DNA says they must descend from the marriage of Whitwell Butler and Belinda Yielding. For the full proof see here.
BUTLER cousin numbers are uncertain:
- BUTLER descends from the marriage of Whitwell Butler and Belinda Yielding. However the exact descent is uncertain.
- For cousin numbers, we assume that Thomas and Tobias Butler are grandchildren of Belinda Yielding.
- When comparing with Belinda Yielding descendants, we need a more precise guess. Which son of hers is father of Thomas and Tobias? For the purpose of getting cousin numbers, we assume it is her son James. But we may be wrong.
- YIELD.2 is a proven descendant of James. So above we show a close estimated cousin relationship of BUTLER and YIELD.2. This is an estimate, but DNA (below) suggests it is true.
ROB.1 is also in YIELD.
- ROB.1 descends from both ROB and YIELD.
- Knowing who ROB.1 is, it makes more sense to think of it as in ROB.
YIELD.1 is also in ROB.
- YIELD.1 descends from both ROB and YIELD.
- Knowing who YIELD.1 is, it makes more sense to think of it as in YIELD.
- We could maybe have a "ROBYIELD" group, for samples in both ROB and YIELD. Although that would include BART too. Maybe best to just give them some marking, and note they are in multiple groups.
Because the ROB samples so far are also in YIELD, for the moment everyone has proven common ancestor Richard Yielding (born around 1710-15).
When there are two lines by which cousins are related, we use the closest cousin numbers.

Total segment matches (minimum segment 9)

We start the DNA analysis by considering total segment matches, using minimum segment size = 9 cM.
9 cM is generally considered significant.

The DNA more or less makes sense:

The tightly related group of BART 1, 2 and 3 match as expected.
BART.7 matches them as expected.
The BUTLER group matches as expected.
The big finding is that our estimate of a close cousin match of BUTLER and YIELD.2 is proved true by the DNA.
4th cousins may match or not match:
- The 4th cousins ROB.1 and YIELD.1 match. The common ancestor is Richard Massy Yeilding (bapt 1773).
- The 4th cousins BUTLER.1 (and BUTLER.2) and YIELD.2 match. The common ancestor is estimated to be James Butler (born 1780).
- BART 6 and 4 are 4.1 cousins but do not match. Such false negatives are common at this level. We need more samples to see the big picture.
5th cousin match:
- Most 5th cousins do not match.
- An exception is ROB.1 and BART.4, which do match. They are related two ways. They descend from both Robert Blennerhassett and Richard Yielding.
6th cousin match:
- Most 5th cousins do not match.
- An exception is YIELD.1 and BART.7, which do match. They are related two ways. They descend from both Robert Blennerhassett and Richard Yielding.
- There are other modest 6th cousin matches.

Total segment matches (minimum segment 7)

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.

Largest segment in match

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.

The normal Blennerhassett/Yielding tree is supported by the DNA. There are some false negatives once you get to 4th cousin.
The addition of the Thomas Butler line to the Yielding tree is also supported by the DNA.

Estimated MRCA

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.

Here is the known cousins table again:

The Gedmatch estimated MRCAs are a fairly good fit to the family tree.
We need more samples to see the bigger picture.