Interpreting 111-marker Y-DNA results

[TwiddlingThumbs]

Questions: When Y-DNA markers undergo mutations, do the number of STRs associated with a marker increase or decrease?

They can go either way.

Do the changes in the number of STRs associated with a marker tell me which DNA Donor has the oldest DNA?

Not sure what you mean by "oldest." Closest to that of the common ancestor? If so, the answer is no, the absolute number of STRs is not relevant; the key is the genetic distance from the STR values of the common ancestor. If (and this is a huge if) you had results for a random sample of descendants of the common male ancestor, the modal values for the group should be approximately those of the common male ancestor. However, since the results are almost certainly not a random sample of descendants, the modal values will be skewed and may or may not be approximately those of the common male ancestor.

[TMS]

Interpreting 111-marker Y-DNA results

P.S.
These men do not match each other in Family Finder, do they?

• AncestryDNA. Adoptee Donor #1 and Hicks Donor #2: Putative 3rd Cousins 1x removed, 96 centimorgans shared across 6 DNA segments.
• FTDNA Family Finder. Adoptee Donor #1 and Hicks Donor #2: 139 centimorgans across 25 segments.

[dna]

Good evening Terry, a guru would know much more than me, but here is my basic knowledge.

[----] When Y-DNA markers undergo mutations, do the number of STRs associated with a marker increase or decrease?

Either. However, in a large population of related men, some directions (and values) are usually seen as more likely. Again, that is for populations.

Do the changes in the number of STRs associated with a marker tell me which DNA Donor has the oldest DNA?

In a large population, where some additional information is provided by tested SNPs, ancestral values can be inferred. I.e. if 100 men tested have value of "15" and only a couple have different values, "15" can be taken to be the ancestral value. 100 is a good number, sometimes 30 might be enough. I would not venture a guess with only 3 men.

Judging by the last names provided, these three men belong the haplogroup R1b and thus it is very likely that there exists an active surname project administered by someone with the insight into the very questions you had asked.


Adding a Big Y test or a cheaper SNP pack test to at least one of the kits would help in answering your questions, since that would definitely place these men into a (genetic) population they belong to. Moreover, if it were to happen that there is no active relevant surname project, you would be able to obtain assistance from a haplogroup project.

[Added in a later edit] Since a surname can have multiple unrelated ancestors, SNP testing would even help if there is an active and relevant surname project.


Good luck - Mr. W.


P.S.
These men do not match each other in Family Finder, do they?

[TMS]

• Y-DNA of 3 male donors has been analyzed to the 111-marker level.
• Donor #1's pedigree chart traces his surname to a Hicks (c. 1760- 1801).
• Donor #2 is an adoptee.
• Donor #3’s pedigree chart traces his surname to a Carter (c. 1675-1715).
• Donor #2's AncesryDNA matches strongly support my claim that Donor #2 is a descendant of my father's maternal grandparents. Consequently, the Adoptee Donor #2 is either a Hicks (Scenario 1) or a Byrne (Scenario 2).

https://drive.google.com/file/d/1vNm...ew?usp=sharing

https://drive.google.com/file/d/1vy-...ew?usp=sharing

• Donor #1 has two matches who have tested to the 111-marker level.
(i) Carter Donor #3 – 109/111 markers; Gen. Distance: 2
(ii) Adoptee Donor #2 – 108/111 markers; Gen. Distance: 4
• Donor #2 has two matches who have tested to the 111-marker level.
(i) Carter Donor #3 – 109/111 markers; Gen. Distance – 2.
(ii) Hicks Donor #1 – 108/111 markers; Gen. Distance – 4.

https://drive.google.com/file/d/1cjX...ew?usp=sharing

• Donor #1 has five Carter-surname matches who have tested to the 67-marker level.
(i) Gen. Distance between Hicks Donor #1 and three Carter-surname donors – 3.
(ii) Gen. Distance between Hicks Donor #1 and two Carter-surname donors – 4.
• Donor #1 has two Carter-surname matches who have tested to the 37-marker level.
(i) Gen. Distance between Hicks Donor #1 and one Carter-surname donor – 3.
(ii) Gen. Distance between Hicks Donor #1 and one Carter-surname donor – 4.
• Donor #2 has five Carter-surname matches who have tested to the 67-marker level.
(i) Gen. Distance between Adoptee Donor #2 and two Carter-surname donors – 2.
(ii) Gen. Distance between Adoptee Donor #2 and two Carter-surname donors – 3.
(iii) Gen. Distance between Adoptee Donor #2 and one Carter-surname donor – 4.
• Donor #2 has two Carter-surname matches and one Cockbill-surname match who have tested to the 37-marker level.
(i) Gen. Distance between Adoptee Donor #2 and one Carter-surname donor – 2.
(ii) Gen. Distance between Adoptee Donor #2 and one Carter-surname donor – 3.
(iii) Gen. Distance between Adoptee Donor #2 and one Cockbill-surname donor – 4.

Conclusion #1: Scenario 1 correctly places Adoptee Donor #1 among Hicks descendants of the Most Recent Common Ancestors, i.e. Donor #1 is a Hicks, not a Byrne.
Conclusion #2: Hicks descendants of the MRCAs are Carters, not Hicks.

Questions: When Y-DNA markers undergo mutations, do the number of STRs associated with a marker increase or decrease? Do the changes in the number of STRs associated with a marker tell me which DNA Donor has the oldest DNA?

--Terry Sampson