Chromosome 2 Triangulation Analysis

The Donaghmoyne Network case study has long faced a structural limitation in its DNA evidence base. The Hamall direct line — Owen Hamall (1847–1898) → Thomas Henry Hamall (1880–1938) → Thomas Eugene Hamall (1904–1967) → the subject's father — narrowed in successive generations to single surviving children carrying the Hamall paternal inheritance forward. The subject's father, Thomas Kenny Hamall, died without testing his DNA. No paternal-line first, second, or third cousins exist. The five children of Thomas Kenny who have tested are siblings to one another and therefore share each other's DNA in ways that make sibling-only data structurally insufficient for paternal-line triangulation.

The implication for the Donaghmoyne research has been significant. Each of the four documented Donaghmoyne couples has been corroborated within its own descendant lines: the James Hamill & Ann Gartlan sibling group through Peter Hamill's 1949 death certificate and supporting DNA, the Owen Hammel & Ann King family through Wisconsin descendants, the Susan Hamill & Charles McCanna family through Joliet descendants. But the cross-line evidence — whether Henry Hamall, Owen Hammel, James Hamill of Dian, and Susan Hamill McCanna's father were brothers, first cousins, or more distantly related — has been carried by autosomal matches at threshold levels (typically 8–34 cM) that could be explained by either true descent from a common ancestor or by chance.

The December 2025 DNA Evidence Analysis page concluded that segment triangulation and Y-DNA testing would be the next steps required to strengthen the case beyond suggestive matching. This page reports the results of the segment-triangulation work that has since been completed, along with a methodological development that resolves the Chicago-line bottleneck without requiring Y-DNA: the construction and validation of a reconstructed paternal kit representing Thomas Kenny Hamall's paternal genome, built from his children's DNA using his wife's kit as a phasing reference.

The reconstructed kit makes possible the analytical step that was previously unavailable to this case study: each cluster match can now be tested directly against the subject's father's reconstructed paternal DNA, producing individually documented paternal-inheritance confirmation in addition to the cluster-level patterns previously available. The combination of mathematical triangulation across multiple platforms with reconstructed-kit one-to-one paternal verification produces segment evidence at the level of rigor sought by the December framework — and makes claims now possible that the earlier evidence base could not support.

The reconstructed paternal kit was produced through the Borland Genetics third-party reconstruction workflow, which builds a parent's genome from the DNA of multiple children and a co-parent. The conceptual basis is straightforward. Each child inherits exactly half of their DNA from each parent, and the inheritance patterns of full siblings overlap on roughly 50% of their genomes. By comparing each child's DNA against their mother's kit and identifying the segments that did not come from her, the algorithm extracts each child's paternal contribution. The four resulting paternal-only datasets are then merged into a single composite kit representing the deceased father's paternal genome.

For this analysis, the inputs were four of Thomas Kenny Hamall's five children — three 23andMe kits (the subject and two siblings, C. and K.) and one FTDNA kit (A., who was unable to provide saliva samples and therefore tested via FTDNA's cheek-swab protocol) — plus the maternal kit (the subject's mother, Barbara O'Brien Hamall). The fifth sibling, E., tested at Ancestry rather than 23andMe and was not used as input to the reconstruction; her role as independent validation is described in Section 2.2. The mother's kit functions as a phasing reference: any DNA in a child's kit that matches the mother's kit is excluded from the paternal extraction, leaving only the paternal contribution. The merged paternal dataset was uploaded to GEDmatch as a research kit, where it can be compared one-to-one against any other kit in the GEDmatch database.

One operational constraint of the resulting kit is significant for the methodology that follows. GEDmatch designates Borland-derived reconstructed kits as research kits, which restricts them to one-to-one comparisons. The standard one-to-many search that allows a tester to discover unknown matches is not available for research kits. Identifying candidate paternal matches therefore proceeds through indirect methods — running one-to-many searches on the subject's own kit and her siblings' kits, identifying matches that appear paternal-side based on shared-match patterns, and then running each candidate one-to-one against the reconstructed kit for confirmation.

The reconstructed kit's accuracy was validated by comparing it one-to-one against each of Thomas Kenny Hamall's five children. For a true parent-child comparison, GEDmatch's one-to-one tool returns characteristic statistics: a total Half-Identical Region (HIR) shared cM value of approximately 3,400–3,600 (each child shares roughly half a parent's genome), an estimated MRCA of one generation, near-complete coverage of the comparable SNPs, and a high full-identical-by-descent percentage indicating both alleles match on most compared positions. Any reconstruction that fails to produce these characteristics for known children is producing artifactual rather than accurate inheritance data.

Four of the five comparisons were against children whose kits contributed to the reconstruction itself — three from 23andMe and one from FTDNA. These comparisons confirm the algorithm successfully integrated each input — but because each contributing sibling's data is part of the reconstruction, their comparisons reflect both true paternal inheritance and reconstruction-input overlap. They are not, strictly speaking, independent tests of reconstruction accuracy.

The fifth comparison was against E., the subject's sister who tested at Ancestry rather than 23andMe and was not used in the reconstruction. Her kit was uploaded to GEDmatch from her Ancestry raw data file. Her comparison against the reconstructed kit is therefore structurally independent: her DNA is not part of the reconstruction's input, so any match between her kit and the reconstructed kit reflects genuine inheritance from the same biological father — not algorithmic overlap. This independent platform validation is the gold-standard test for reconstruction accuracy.

The reconstruction methodology therefore drew on three independent SNP-chip platforms across input and validation: 23andMe (three contributing siblings), FTDNA (one contributing sibling, A.), and Ancestry (E. as independent validation reference). Cross-platform input diversity strengthens reconstruction integrity by reducing dependence on any single platform's chip design.

All five comparisons return the GEDmatch one-to-one tool's estimate of one generation to MRCA — confirming the reconstructed kit functions correctly as a parent-child comparator. The four contributing siblings show HIR coverage between 85.90% and 99.92%, with the variation reflecting each sibling's individual role in the reconstruction algorithm. A.'s near-perfect 99.92% coverage suggests her kit served as a primary phasing anchor; the others' coverage reflects fill-in contributions across the algorithm's processing.

E.'s comparison is the most analytically important result in the table. Her Ancestry kit was tested on a different SNP chip than the 23andMe kits used in the reconstruction, and the comparable SNPs between the two chips are limited — only 148,461 SNPs were available for the comparison versus 423,000–436,000 for the contributing siblings. Despite this reduced SNP density, E.'s comparison returned a Total HIR of 2,500.8 cM, a 1-generation MRCA estimate, and a full-IBD percentage of 67.14%. These values are consistent with a true parent-child relationship measured at lower SNP resolution. With the same SNP count available to her as her siblings had, her HIR would almost certainly land in the 90–95% range. The proportional pattern at the available SNPs already confirms the reconstruction produces accurate paternal inheritance data.

The reconstructed kit could be improved in coverage by adding E.'s Ancestry kit as a fifth sibling input. Five-sibling reconstructions typically reach 90–95% paternal coverage versus the 75–90% range of four-sibling reconstructions. Adding E. would close some of the segment gaps, potentially surfacing additional paternal matches that the current reconstruction does not detect.

However, adding E. to the reconstruction would eliminate her function as the independent platform validation reference. Any subsequent comparison against the reconstructed kit would no longer have a structurally independent test point. For a research project that aspires to BCG portfolio standards and that may be evaluated by reviewers familiar with reconstruction methodology, the independent validation reference has substantial methodological value.

The decision documented for this analysis: E.'s kit is retained as the validation reference. She has not been added to the reconstruction. Should subsequent research identify a specific paternal coverage gap that her DNA could fill, this decision is reversible, but the marginal coverage improvement does not currently justify trading away the independent validation. This decision is recorded in the project's research log.

Before any segment was painted or any triangulation claim was advanced, the chromosome 2 cluster was identified through four independent paths across three DNA-testing platforms. Cross-platform convergence on the same chromosomal region constitutes robust cluster identification: no single platform's algorithm or matching threshold determined the finding.

The first identification path used 23andMe's Cluster Relatives in Common feature with P.H. (the highest-cM cluster member at 38.5 cM with the subject) as the anchor. Selecting P.H. and requesting in-common-with matches surfaced a coherent grouping of paternal-side matches: S.M., M.R., B.R., T.S., D.O., J.L. and others. The 23andMe cluster did not name specific chromosomes, but the matches' segment data (visible on each match's individual page) consistently included shared chromosome 2 regions in the 35–60 megabase area.

The second identification path used GEDmatch's Compact Segment Mapper applied to the subject's top 15 matches. The visualization rendered each match's largest shared segments across all chromosomes simultaneously, and chromosome 2 stood out immediately as the densest stacking area. Eight to nine of the top fifteen matches had segments overlapping in roughly the same chromosome 2 region, with no comparable density on any other chromosome.

The third identification path used GEDmatch's "people who match both kits, or 1 of 2 kits" search applied to the subject's kit and P.H.'s kit. This surfaced individuals matching both — a list that overlapped substantially with the 23andMe cluster but added several GEDmatch-only matches (J.S., A.D., D.O.) not visible through 23andMe's tools.

The fourth identification path used MyHeritage's chromosome browser, which independently surfaced a chromosome 2 paternal cluster among the subject's MyHeritage matches. The MyHeritage cluster overlapped substantially with the GEDmatch and 23andMe clusters but added several MyHeritage-exclusive matches (A.W., A.C., A.B., R.S.) — particularly testers who had uploaded to MyHeritage from Ancestry and were therefore not visible through 23andMe.

The four identification paths converged on the same chromosomal region from different starting points and different match pools. This convergence is the strongest available pre-triangulation signal that the cluster represents genuine shared ancestry rather than algorithmic artifact.

Mathematical triangulation establishes that multiple matches share the same physical DNA segment with the kit owner and with each other simultaneously — a pattern explainable only by descent from at least one common ancestral source. This section presents the chromosome 2 triangulation evidence at three nested levels: MyHeritage's algorithmically-confirmed triangulation groups (TG1 and TG2), 23andMe's segment-level data revealing three separable sub-clusters, and the cross-platform conservative core where all three platforms converge on the same shared region.

MyHeritage's chromosome browser includes a triangulation tool that mathematically confirms when multiple selected matches share the same DNA segment with each other and with the kit owner simultaneously. Unlike one-to-one comparison, which only verifies bilateral sharing, triangulation establishes that all selected matches share the same physical DNA segment.

TG2's coordinates are nested within TG1's — TG2 (44,599,253 – 50,854,610) sits inside TG1 (44,343,676 – 51,515,672). This is the expected behavior when MyHeritage's algorithm computes the minimum shared region across different match subsets. TG2 represents the conservative core: the smallest segment that all seven of its members definitively share. TG1 represents the broader region shared by its six members. Both groups identify the same underlying ancestral segment.

Combining the membership of both groups yields nine unique MyHeritage matches confirmed mathematically triangulating on chromosome 2: B.H., A.W., J.K., R.S., M.G., B.R., A.C., A.B., R.C. Four matches (B.H., A.W., M.G., J.K.) appear in both groups, providing the strongest individual-match triangulation confirmation.

The MyHeritage triangulation work in 4.1 and 4.2 demonstrated mathematical confirmation of nine matches sharing a chromosome 2 segment. Adding 23andMe segment-level data to the analysis reveals that the chromosome 2 paternal contribution is more analytically structured than the MyHeritage core alone suggests. Twenty-three 23andMe matches with captured chromosome 2 segment coordinates resolve into three separable sub-clusters, occupying overlapping but distinct regions of chromosome 2. Each sub-cluster carries a different surname signature, and each appears to represent a genealogically distinct ancestral contribution.

Sub-cluster Cluster A — the deeper Hamill origin. Three matches share segments beginning at approximately 30.3–30.5 megabases — earlier on the chromosome than any Cluster B or C match. T.S. (24.50 cM, 30,526,780 – 51,604,274) and R.vE. (27.40 cM, 30,319,618 – 52,338,106) triangulate at approximately 21 megabases of shared segment. N.L. shares a smaller segment overlapping the cluster's right edge (11.20 cM, 43,121,284 – 51,514,659). T.S.'s line traces through documented County Monaghan Hamill ancestry (Worked Example 1, Section 7); R.vE. and N.L. both descend from Owen Hammel and Nancy King of the Wisconsin Hammel branch — a separate emigrant family explicitly distinct from the subject's own Owen Hamall (1847–1898) line. The earlier segment start position and the Hamill-only surname signature suggest this cluster represents a deeper Hamill origin pre-dating the divergence of the subject's Donaghmoyne paternal Hamill family from the Wisconsin emigrant Hammel family.

Sub-cluster Cluster B — Trainor, Macaslin, and the Louth-side maternal/spousal network. Seven matches cluster between approximately 35.7 and 85.4 megabases, with a Trainor-Macaslin core extending rightward beyond the Cluster C endpoint. The largest segment in this cluster (49.32 cM) belongs to F.R., the father of B.R. (Worked Example 2 in the December 2025 page). Other Cluster B members include K.W., G.Wo. (a documented second cousin of K.W.), M.D.S., J.Su., C.A., M.K., and H.R. The surname signature concentrates in Trainor, Macaslin, Gartlan, Thornton, McArdle, McParland, Killough, Shevlin, and McGurk — surnames concentrated in the Louth–Monaghan border region (Carrickmacross, Inniskeen, extending into Termonfeckin and Dundalk in County Louth). Cluster B appears to represent collateral marriages of the Donaghmoyne Hamill/Hammel paternal line into Louth-side spousal families rather than the paternal Hamill line itself.

Sub-cluster Cluster C — the Donaghmoyne paternal endogamous core. Ten matches cluster between approximately 36.07 and 75.55 megabases, with a densest overlap zone at 36,862,239 – 52,883,758 (approximately 16 megabases shared by all Cluster C members). This cluster contains P.H. (Worked Example 3) along with J.R., C.F., D.E., D.M., J.McG., J.C., G.W., B.U., and (with shorter segments) K.McE., L.H., and J.D.E. The surname signature is the densely interconnected McEneaney / McGeough / Hoey / Woods / Rooney / McGurk / Marron / Hanratty / Finegan / Crosby / McMahon network of the Donaghmoyne and Inniskeen Catholic parishes. Cluster C is the Donaghmoyne paternal endogamous core — the cluster within which MyHeritage TG1 and TG2 sit (see Section 4.4).

Within Cluster C, an identical-boundary sub-cluster. Three Cluster C matches — J.C., G.W., and B.U. — share segments with the subject that are identical to the SNP. All three boundaries are 36,862,239 – 59,041,432, all three at 21.09 cM and 4,682 SNPs. Identical-SNP boundaries across three independent matches are not the typical signature of distant cousin matches, where individual segments overlap but boundaries vary. Identical boundaries indicate either a tight recombination hotspot at those exact coordinates or descent from a shared ancestor through paths recent enough that the segment hasn't recombined further. Tree analysis of all three matches resolves the ambiguity: all three converge on Peter McGeough (1788–1869) of the Donaghmoyne McGeough core (see Worked Example 4, Section 7).

Aligning the segment coordinates from all three platforms reveals that the 23andMe Cluster C conservative intersect (36,862,239 – 52,883,758) fully contains both MyHeritage triangulation groups: TG1 (44,343,676 – 51,515,672) and TG2 (44,599,253 – 50,854,610). Three independent platforms — 23andMe segment matching, MyHeritage's mathematical triangulation algorithm, and GEDmatch one-to-one comparison against the subject's father's reconstructed paternal kit (Section 5) — independently detect the same chromosome 2 paternal Donaghmoyne segment.

The smallest region confirmed by all three platforms simultaneously is the segment at 44,599,253 – 50,854,610: 6.25 megabases, MyHeritage TG2's coordinates. This is the conservative cross-platform-confirmed core. Every match populating this region is detected as a triangulation member by MyHeritage's algorithm, falls within the 23andMe Cluster C boundary, and (for those matches accessible on GEDmatch) returns a confirmed paternal segment when compared one-to-one against the reconstructed kit.

The three-cluster structure described in Section 4.3 was identified by manually comparing 23andMe-captured segment coordinates and surname signatures across the cluster's 23andMe matches. An independent line of evidence for the same three-cluster structure comes from 23andMe's DNA Relatives Clustering tool — a machine-learning system that groups a tester's matches into clusters based on patterns of shared DNA among them, without using segment-position information.

Running the clustering tool with D.E. (one of the central Cluster C matches in the segment-level analysis) as the "Relative in Common" anchor produced twelve clusters. The three largest clusters correspond directly to the three sub-clusters identified by segment analysis. Cluster 1 (twenty-five members) contains the main Donaghmoyne paternal core: P.H., G.W., D.E. herself, J.C., B.U., J.R., C.F., D.M., F.R., H.R., and thirteen additional matches not previously captured in the segment-level analysis (designated C.D., J.H., J.M., C.F.₂, A.J., J.D., M.F., J.K., A.C., L.Ga., A.S., L.G., and A.Sm. — all anonymized to initials pending tree investigation). This cluster corresponds to Cluster C from Section 4.3. Cluster 2 (four members) contains R.vE., R.C., L.Lo., and T.S. — corresponding precisely to Cluster A, the deeper Hamill origin. Cluster 3 (three members) contains B.R., G.Wo., and K.W. — corresponding to Cluster B, the Trainor/Louth-side network.

The remaining nine clusters in the D.E. clustering view contain singletons or small two-to-three person groupings (J.D.E. + K.McE., M.K., a Schmitz/Freis pair, an Arteau/Gerlach/Serge triplet, and individual singletons). The Schmitz/Freis and Arteau/Gerlach groupings carry German and French-Canadian surname patterns that suggest they represent D.E.'s ancestral lines unrelated to the Donaghmoyne paternal core; investigating whether they appear in the subject's own clustering view (rather than D.E.'s) would confirm or refute that interpretation.

A subsequent analytical update extends this algorithmic corroboration across five additional clustering snapshots, each anchored on a different focal match within the cluster's match population. The five anchoring views capture: a T.S. focal context (47 matches resolving into 9 clusters); an L.F. anchor (a focused 7-match view that isolates the Wisconsin Hammel sub-cluster as Cluster 1 with R.C. + R.vE. + L.Lo. + L.F. co-occurring as expected); a J.H. focal context (43 matches, 9 clusters); a K.McE. focal context (38 matches, 11 clusters); and an F.R. focal context (50 matches, 11 clusters).

Across all five anchoring views, three sub-cluster patterns consistently emerge with cluster membership corresponding to the structural Cluster A/B/C distinctions identified by segment-position analysis. The Wisconsin Hammel sub-cluster (R.C. + R.vE. + L.Lo. + T.S., with L.F. surfacing in the L.F.-anchored view) maps consistently to Cluster A across the snapshots. A Trainor-adjacent sub-cluster — B.R. + K.W. + C.A. + J.Su. — maps to Cluster B in the J.H., K.McE., and F.R. anchored views. The McEntegart–Holzman sub-cluster (K.McE. + L.H., with J.D.E. surfacing in some snapshots and R.C. surfacing in the K.McE.-anchored view) intersects Cluster C's boundary with the smaller sub-cluster groupings.

One observation worth flagging from the multi-anchor data: R.C. appears in the Wisconsin Hammel sub-cluster in the T.S. and L.F. anchored views and in the McEntegart–Holzman sub-cluster in the K.McE.-anchored view. This cross-cluster appearance pattern is consistent with R.C.'s documented descent (via his first cousin T.S.) from a Hamill paternal line that places him kin to multiple cluster sub-groups simultaneously — the Andrew Hamill (1793–1866) chain through James Anthony Hamill (1818 Monaghan) and his son's wife Catharine Hamill Webb. T.S. and R.C.'s documented Hamill chain was extended in subsequent research-log work back through Anthony Hamill (1750–1820) m. Margaret Hood Hamill (1756–1824) to John J Hamill m. Annis Lettice Dinsmore. The deeper Anthony + Margaret Hood couple is independently corroborated by parallel descent in another DNA-tested line (a separate cousin researcher's tree converging on the same Anthony Hamill couple), strengthening the case for this being a documented common ancestor rather than a tree-attestation artifact.

Mathematical triangulation establishes that multiple matches share the same chromosomal segment, but it does not establish whether that shared segment was inherited through the paternal or maternal line. For the Donaghmoyne research question, the distinction is essential: a segment shared through the maternal O'Brien-Robertson line would not bear on the Hamall paternal-line hypothesis at all.

The reconstructed paternal kit allows direct paternal-line confirmation. For any match in the chromosome 2 cluster, a one-to-one comparison against the reconstructed kit returns a definitive result: a confirmed paternal segment, no significant shared cM (indicating a maternal-line connection), or a coverage gap (the shared region falls in a part of the paternal genome not captured by the reconstruction).

One operational note constrains the workflow. GEDmatch is currently the only platform supporting one-to-one comparisons against research kits. The reconstructed kit cannot be tested against MyHeritage-only matches (A.W., A.C., A.B., R.S., R.C.) because those matches' raw DNA has not been uploaded to GEDmatch. Their triangulation through MyHeritage's mathematical tool stands as confirmed shared segment evidence, but their paternal inheritance cannot be independently verified through the reconstructed kit. The same caveat applies to many of the 23andMe-only matches in Section 4.3 whose kits have not been transferred to GEDmatch (Section 5.3 lists these as a separate evidence layer). For the matches available on GEDmatch, the one-to-one results below constitute the most rigorous form of paternal-inheritance documentation currently available for this case study.

P.H.'s comparison against the reconstructed kit returned three confirmed paternal segments — the chromosome 2 main cluster region, plus two additional segments on chromosome 4 (7.2 cM) and chromosome 16 (7.3 cM). The two additional segments are above the standard 7 cM IBD reliability threshold but at its lower bound, and they are flagged accordingly in the project's research log.

Multi-chromosome paternal sharing is significant for two reasons. First, it indicates that P.H.'s total shared cM with Thomas Kenny Hamall (across all three segments) is meaningfully higher than P.H.'s 38.5 cM total shared cM with the subject. The combined evidence is consistent with a 3rd-cousin to 3C1R relationship range — closer than the typical 4th-cousin range that single-cluster-segment matches tend to occupy. Second, multi-chromosome sharing supports a closer MRCA estimate. A single shared segment can survive recombination across many generations; multiple independent segments are more likely to indicate fewer generational distances. The combined evidence places P.H.'s most recent common ancestor with the subject's father in the 1820s–1850s Donaghmoyne generations, consistent with the documented timeframe of the four-couple Donaghmoyne network.

Beyond the matches in the Section 5.1 table, an additional set of 23andMe matches has captured chromosome 2 segment data placing them within the cluster, but their kits have not been transferred to GEDmatch and therefore cannot be tested one-to-one against the reconstructed paternal kit. Their evidentiary status sits at MyHeritage Tier 1 (mathematical triangulation across multiple platforms when their segments are also detected by MyHeritage) plus 23andMe segment-level cluster confirmation, but not at the reconstructed-kit Tier 2 of Section 5.1. The table below documents these matches with their captured segment coordinates and surname signatures.

Beyond the segment-level evidence on chromosome 2, the cluster's matches share a distinct surname signature in their documented ancestry. Cross-tabulating the documented family connections of all cluster matches yields a recurring set of surnames concentrated geographically in southeast County Monaghan and adjacent County Louth. The surname pattern is independent corroboration of the segment evidence: it is not derived from the DNA itself but from primary-source documentation of each match's ancestral lineage, and it concentrates in a specific micro-region that would not be expected if the cluster represented broader Irish or general European ancestry.

The geographic concentration is the central analytical fact. The surnames distribute primarily across four parishes — Donaghmoyne, Magheracloon, Inniskeen, and Carrickmacross — in southeast County Monaghan, with extensions into adjacent County Louth (Termonfeckin and Dundalk). This corresponds to a coherent pre-Famine Catholic community of approximately 15–25 square miles, within which the documented marriage patterns show repeated intermarriage across the same surname families over three generations.

The pattern is genetically and demographically consistent with an endogamous parish community: a Catholic population restricted in marriage choice by religious affiliation, geographic isolation, and limited transportation, in which the same families intermarried repeatedly. For DNA matching, endogamy produces exactly the signature observed here — multiple independent surname lines sharing the same chromosomal segments because they all descend from a small founding population that contributed DNA broadly across the community.

What the surname signature does not establish on its own is any specific most-recent-common-ancestor relationship between the subject's direct line and any individual cluster member. Identifying that a cluster of matches descends from a small Donaghmoyne population is a population-level finding, not a genealogical one. The genealogical work — identifying the specific ancestral couple through whom the subject and a given match share descent — requires documentary research in pre-Famine and early-Famine Catholic parish records. The Peter McGeough finding in Worked Example 4 is the first specific MRCA identified at this level for the chromosome 2 cluster; the Trainor-Hamill Michigan branch (Section 10 Path Forward) is the next candidate currently in active investigation.

The full analytical workflow is most clearly demonstrated through specific worked examples. Each of the four below shows how the methodology was applied to one match or one MRCA identification, what the evidence established, and what remains open for future research.

The December 2025 DNA Evidence Analysis page used a four-tier evidence framework: PROVEN, SUGGESTIVE, EXPLORING, and INDIRECT. The chromosome 2 evidence requires adding a higher tier and updating where specific connections sit. The framework below carries forward the December tiers and adds a new top-level CONFIRMED tier for findings now backed by segment-level triangulation plus reconstructed-kit paternal verification plus multi-platform cross-validation.

An endogamous Donaghmoyne genetic population exists as an identifiable cluster, demonstrated through cross-platform segment evidence at five layered levels: independent identification through multiple search paths, mathematical triangulation across nine MyHeritage matches, 23andMe segment-level resolution into three distinct sub-clusters, cross-platform convergence on a 6.25 megabase conservative core confirmed by all three platforms, and direct paternal-inheritance confirmation through one-to-one comparison against the subject's father's reconstructed kit for at least nine GEDmatch-accessible cluster matches.

The subject's paternal line descends from this population. The reconstructed paternal kit demonstrates that segments shared between cluster matches and the subject also are shared between cluster matches and the subject's father directly, eliminating maternal-line ambiguity for the chromosome 2 cluster region.

Peter McGeough (1788–1869) of Donaghmoyne is documented as MRCA for the identical-boundary sub-cluster, with three independent descendant lines converging on him through tree analysis and SNP-precise segment evidence corroborating the kinship structure. This is the chromosome 2 cluster's first specific-MRCA-level finding.

Three distinct ancestral signals on chromosome 2 are documented through 23andMe segment-level analysis and corroborated by 23andMe's machine-learning DNA Relatives Clustering algorithm operating independently on shared-DNA patterns: a deeper Hamill origin (Cluster A / 23andMe Cluster 2) shared by Donaghmoyne, Wisconsin, and Michigan emigrant Hamill branches; a Louth-side spousal/maternal network (Cluster B / 23andMe Cluster 3) carrying Trainor, Macaslin, Gartlan, and related surnames; and the Donaghmoyne paternal endogamous core (Cluster C / 23andMe Cluster 1) within which Peter McGeough's identical-boundary sub-cluster sits. Segment-position analysis and machine-learning shared-DNA clustering converged on the same three-cluster grouping with cluster membership corresponding precisely between the two methods.

Cross-line genetic continuity is documented across at least 25 independent matches (with chromosome 2 segments captured) and 22+ recurring surnames concentrated in southeast Monaghan and adjacent Louth — a geographic specificity inconsistent with general Irish or European ancestral matching.

The Chicago paternal-line bottleneck that previously limited the case study's evidence base no longer constrains paternal-line analysis. The reconstructed paternal kit provides a stable comparator for any future paternal candidate match transferred to GEDmatch.

Specific most-recent-common-ancestor relationships for most pairs of cross-line matches at five-or-more generations distance remain unestablished. The Peter McGeough finding is one specific MRCA identified for one sub-cluster; the broader question of MRCA-level relationships across the four documented Donaghmoyne couples (James Hamill of Dian, Owen Hamall, Owen Hammel, Susan Hamill McCanna) remains open. The Trainor + Mary Hamill (1800) Michigan branch is documented as existing but its specific relationship to the subject's parental Hamill line awaits Mary Hamill's birth parish documentation.

Pre-1830 Donaghmoyne genealogy has not been resolved by this analysis. Catholic parish baptismal and marriage registers for Donaghmoyne begin in 1834. Earlier ancestral identification — including the parental generation of Peter McGeough (1788–1869), the wife-identity ambiguity for Peter, and Mary Hamill's (1800) birth parish and parents — requires alternative pre-Famine sources (Catholic Qualification Rolls 1778–1790, surviving estate records, the Morpeth Roll 1841, Tithe Applotment Books 1823–1838) that have not yet been systematically searched for the relevant family lines.

The P. McGue McGeough (1800) ↔ Peter McGeough (1788–1869) sibling hypothesis — which would tie the Trainor-Hamill Michigan branch directly into the Donaghmoyne McGeough paternal core via the Mary E. Trainor McGue + Lawrence McGue marriage — is documented as a research lead at Exploring tier and awaits pre-Famine documentary evidence.

User-tree attributions of pre-1800 ancestry remain suggestive but unverified. The recurring James Hamell I (1652–) ancestor in multiple cluster trees is an example: the attribution may reflect community-shared use of an early-published genealogy rather than independent primary-source documentation. The hypothesis is reinforced by the observation that the same James Hamell I attribution appears in trees of Hamill-surnamed testers who do not share segments with the subject's father at the 7 cM IBD threshold (including Steven Hammill, whose tree traces directly through Owen Hamell 1731 to James Hamell I 1652, but whose GEDmatch comparison returns zero shared segments with the reconstructed kit). If the deep ancestor were genuinely documented through descent, segment evidence would be expected to vary continuously across descendants; the binary pattern observed (some Hamill-surnamed testers share, some do not, regardless of tree attestation) is more consistent with multiple distinct Hamill paternal lineages converging on a community-shared ancestor narrative than with all the surnamed testers being descended from a single primary-source-documented founder. Until that founding narrative's source is identified and evaluated, the attribution is treated as a research lead rather than as evidence supporting any specific finding.

The Hamill surname is therefore necessary but not sufficient for membership in the Donaghmoyne paternal cluster. The cluster's Hamill signature is specific to one Catholic Donaghmoyne Hamill paternal line — the line shared by the subject's direct ancestry, T.S.'s Andrew Hamill (1793) line, M.S.'s Susan Hamill McCanna line (Worked Example 5), the Trainor-Hamill Michigan branch, and likely M.B.'s Drumaconvern Hamill line. Hamill-surnamed testers descending from Plantation-era Antrim or Down Protestant Hamills (likely the case for Brian S Hamill's "Hercules Hamill" line and possibly Bill H's Samuel Hamill line) or from Tyrone Catholic Hamills (likely the case for E.R.Q.'s Henrico Hamill line) are not part of the Donaghmoyne paternal cluster despite carrying the same surname. This finding strengthens rather than weakens the case study's interpretation: the cluster surname signature is specific, not generic, and reflects descent from a specific Donaghmoyne community rather than any random subset of Ulster Hamills.