[00] Segmentology: Outline of Segmentology (7 May 2015 to 21 Apr 2025)

 

[01] Introduction and Disclaimer – I became a genealogist in 1974; and a genetic genealogist (when I started a Y-DNA surname project) in 2002. I have bought original DNA kits at FTDNA (Y-111 and Big-Y, SNPs, FMS, atDNA), 23andMe, AncestryDNA, Genographic, Genos (exome), LivingDNA and MyHeritage; and uploaded to Y-Search, mitoSearch, NIH, GEDmatch, and DNA.Land. I present on genealogy and DNA to genealogy groups and conferences. I have no contract, compensation, or allegiance with any company. I am an unpaid volunteer at GEDmatch; a Surname Project Admin at FTDNA; and a long-time subscriber/researcher at Ancestry and FamilySearch. Statements/opinions are my own.

Segment-ology Table of Contents

[01A] Getting Started with Autosomal DNA Part I (22 Nov 2015)

[05] Segments

[02] What is a segment? – Ancestral (true) Segments vs Shared (computer) Segments (7 May 2015)

[03] Measuring Segments – bp (or Mbp); cM; SNP (13 May 2015)

          [03A] Fuzzy Data, Fuzzy Segments – No Worry (30 May 2015)

          [05A] Segments: Bottom-Up (24 May 2015)

          [05B] Segments: Top-Down (1 Jun 2015)

          [05C] CA and MRCA (2 Jan 2016)

          [05D] Crossovers by Generation (2 Feb 2016)

          [22A] Crossover and Segment Formation TIDBIT (2 Jan 2017)

          [22CA] What is the Next Segment (9 Dec 2023)

          [05E] Anatomy of a TG (5 Feb 2016)

          [05F] Sibling Crossovers (3 Dec 2022)

          [05G] The Life of a DNA Segment (4 Jan 2022) *

          [22BD] Bad Segments – Good Segments TIDBIT (30 Sep 2021)

          [22BF] We Match Segments, Not Matches TIDBIT (13 Aug 2023)

          [22U] Confusion about Base Pairs TIDBIT [2 May 2018)

          [22BQ] How To Detect False Matches Theory (6 May 2023)

[06] Segment size vs cousinship

          [06B] Segment Size vs Cousinship –Chart Needed –Estimated Curves (7 Nov 2015)

          [06C] In Defense of Small Segments (21 Jan 2020) (Edit 2 Feb 2020)

          [06D] Distribution of Cousins (9 Dec 2021) (Update/edit 19 Dec 2021)

          [06F] Shared cMs for Small Segments (5 Jun 2024)

          [06Z] VUCA DNA (24 Aug 2015)

[07A] Ancestors – The Porcupine Chart (Biological vs Genetic Ancestors) (7 Aug 2015)

          [07C] Proof of Sticky Segments (16 Nov 2015)

[08] Triangulation Concepts

          [08A] Your TGs are Pretty Unique! CONCEPT (7 Sep 2017)

          [08B] The MRCA Knothole! CONCEPT (9 Sep 2017)

          [08C] MRCA Knothole Guidelines. CONCEPT (10 Sep 2017)

          [08D] Using a Group Common Ancestor. CONCEPT (20 Jun 2020)

          [08E] Can Three Fourth Cousins Share the Same Segment? (12 Aug 2023)

          [22BO] The Two Meanings of TG TIDBIT (7 Apr 2023)

[09] Benefits of Triangulation (9 May 2015)

[10] How To Triangulate: Collect, Arrange, Compare/Triangulate (11 May 2015)

          [10A] Triangulating Your Genome (29 Dec 2020)

          [10C] Triangulation: CA vs MRCA – diagrams [see [05C]

          [10D] Using MyHeritage Labels for Triangulation (15 Dec 2021)

          [10E] Triangulation on a Side Is a Snap (30 Jul 2023)

          [22M] Triangulation at 23andMe TIDBIT (20 Jul 2017)

          [22N] A Triangulation Overview TIDBIT (28 Jul 2017)

          [22BH] Segment Data for Ancestry Matches TIDBIT (6 Jul 2022)

          [22BJ] Segment Data for Ancestry Matches 2 TIDBIT (23 Feb 2023)

[11] Why Triangulation works (1 vs 2 chr; IBD segs)

          [11A] Does Triangulation Always Work? (10 May 2015)

          [11B] Does Triangulation Work? (19 Oct 2015)

          [11D] Are Overlapping Segments Triangulated? (15 Apr 2020]

          [11E] Another Take on Segment Triangulation (10 Sep 2023]

[13] Triangulation vs IBD

          [13A] Small Segments and Triangulation (30 Sep 2015)

          [22BV] Identifying False Shared DNA Segments TIDBIT (18 Jun 2023)

[14] Phasing DNA

          [14A] Phasing Your Ancestors’ DNA? (20 Apr 2022) 

          [14B] A Triangulated Group is an atDNA Haplogroup (2 Aug 2023)

[15] How Triangulated Groups (TGs) play out in practice.

          [15A] Understanding and using TGs (18 Sep 2016)

          [15B] The Attributes of a TG (19 Sep 2016)

          [15G] A Targeted Process at AncestryDNA (20 Oct 2016)

          [15H] Distribution of TGs – Part 1 ( 1 Oct 2021)

        [15I] Distribution of TGs – Part 2 (5 Oct 2021)

        [15J] Distribution of TGs – Part 3 (8 Oct 2021)

        [15K] Distribution of TGs Part 4 (Spreadsheet) (13 Oct 2021)

          [22BL] Triangulated Group Analysis TIDBIT (10 Jan 2023)

          [22D] Only One Comparison Needed to Add a Segment to a TG TIDBIT (2 Jan 2017)

          [22H] One Segment at a Time TIDBIT (18 Feb 2017)

          [22BX] Triangulated Group Segments Are Like mtDNA TIDBIT (28 Jul 2023)

          [22BYa] Triangulation and Clustering Among Companies (28 Oct 2023)

[16] Segment analysis

          [16D] Endogamy PART I – Shared DNA (2 Dec 2015)

          [16E] Endogamy PART II – One Segment from One Ancestor (5 Jan 2016)

          [16F] Segment-ology: Endogamy – Get the Facts! (25 Apr 1922)

          [22B] Number of Matches on a Segment (or TG) TIDBIT (2 Jan 2017)

[18] Pile-ups: Small segments; TG segments (7 Oct 2015)

[19] Clustering

          [19A] Think Icicles! (30 Oct 2018)

          [19B] Icicles – Part 2 and Match Clustering (8 Jan 2019)

          [19C] Shared Clustering – A Great Tool! (29 Nov 2019)

          [19G] A Unified Theory of Genetic Genealogy (16 Dec 2019)

          [19H] Let the Matches Tell Us the Cluster Common Ancestor (20 Jun 2020)

          [22Z] Match Clusters – Chicken or Egg? TIDBIT (11 Feb 2019)

          [22AA] Confessions of a Match Clusterer TIDBIT (14 Feb 2019)

          [22BE] Insights on Clustering vs Triangulation TIDBIT (13 Apr 2023)

[19a] Clustering Tools

          [22AF] Clustering Programs TIDBIT (4 Apr 2019)

          [19C] Shared Clustering – A Great Tool! (29 Nov 2019)

          [19J] Use Clusters! (5 Jul 2020)

          [19K] Breaking Down Brick Walls (3 Feb 2021)

[19b] Manual Clustering

          [22AD] D I Y Clustering TIDBIT (18 Feb 2019)

          [19I] Easy Manual Clustering at AncestryDNA (1 Jul 2020)

          [19L] Manual Clustering From the Bottom Up (15 Feb 2022)

          [19M] Manual Clustering to Find Ancestors (26 Feb 2022)

          [22AQ] Grouping Matches – Try It! TIDBIT (28 Nov 2019)

[19c] Walking the Clusters Back

          [19D] Walking the Clusters Back (1 Dec 2019)

          [19E] Walking The Clusters Back II (5 Dec 2019)

          [19F] Walking the Clusters Back III [14 Dec 2019)

          [19N] Walking The Clusters Back  (22 Aug 2022)

          [19Na] WTCB SITREP (21 Aug 2022)

          [19Nb] WTCB Issue Alt MRCA (26 Sep 2022)

          [19Nc] WTCB SITREP Nov 2022 (12 Nov 2022)

          [19O] WTCB Observations and Advice (30 Nov 2023)

          [22AB] Walking the Clusters Back TIDBIT (14 Feb 2019)

[19d] Misc Clustering

          [22AC] Match Cluster Report 1 (14 Feb 2019)

          [22AE] Clusters Link to TGs and an Apology TIDBIT (22 Feb 2019)

          [22AP] Extending the MRCA of a TG through Clusters TIDBIT (18 Nov 2019)

          [22AT] Clusters at Brick Walls TIDBIT (7 May 2020)

          [22AU] Using Ethnicity to Identify a Cluster TIDBIT (12 Jun 2020)

[21] Genealogy

          [22BG] What Is Your Objective? TIDBIT (8 May 2022)

          [22BC] What Do You Get from a DNA Test TIDBIT [29 Sep 2021)

          [22C] Roughly Right is OK for Genealogy TIDBIT (2 Jan 2017)

          [22BI] It is Iterative TIDBIT (31 Jul 2022)

          [22E] Save the Clues TIDBIT (2 Jan 2017)

          [22F] Walking the Ancestor Back TIDBIT (4 Jan 2017)

          [22I] Format for AncestryDNA Notes TIDBIT (7 May 2017)

          [22L] Using a Child to Determine the Side TIDBIT (12 Jul 2017)

          [22P] Using AncestryDNA Notes TIDBIT (9 Sep 2017)

          [22Q] Make a Resolution to Contact Your Matches TIDBIT (7 Jan 2018)

          [22R] When a Plan Comes Together TIDBIT [17 Mar 2018)

          [22S] Contact Your Match Soon TIDBIT (15 Apr 2018)

          [22V] AncestryDNA Search on Notes TIDBIT (1 Jun 2018)

          [22W] Shorthand ID for Common Ancestors TIDBIT (2 Feb 2019)

          [22AX] Search on a Surname TIDBIT (6 Jun 2021)

          [22AY] Extending a Match’s Ancestry TIDBIT (13 Jun 2021)

          [22AZ] Search on a Surname – Using It Part II TIDBIT (25 Jun 2021)

          [22BA] Two Tricks TIDBIT (9 Jul 2021)

          [22BB] Do You Have a Suspicious Branch in Your Tree? TIDBIT (28 Sep 2021)

          [22CB] Go for the Triple Play (20 Dec 2023)

          [22CC] Quandry (25 Dec 2023)

          [22CD] Gold Stars (29 Dec 2023)

          [22CE] Let the Chips Fall Where They May (1 Jan 2024)

          [22CI] Which Sibling Is the Bio-Ancestor? (3 Apr 2024)

          [22AS] Download Your AncestryDNA Matches in 10 Minutes! (9 Apr 2020; Edit 8 Aug 2020)

          [22AV] Find AncestryDNA Matches with Common Ancestors TIDBIT [8 Aug 2020)

          [22BN] Distant Common Ancestor Couples TIDBIT (7 Mar 2023)

[23] Ancestors

          [23-37P] Breaking Thorough a Brick Wall (5 Aug 2019

          [23-38P] Ahnentafel 38P – John ALLEN Family (26 Jan 2022)

          [23-98Ma] Testing a Guess With Teamwork! (10 Mar 2023)

          [23_98Mb] Percent of Shared Cousins Indicates Relationship (15 Mar 2023)

[30] Bio-Ancestors

          [30A] Bio-Ancestors – Testing a Line (20 Apr 2021)

          [30B] Finding Bio-Ancestors (2 Jun 2022)

          [30C] How Many NPEs Do You Have? (25 Mar 2020)

[35] Tools

[35A] ThruLines at AncestryDNA

          [35AA] AncestryDNA Side vs ThruLines Side (13 Feb 2024)

                (see also these TIDBITS]

          [22AG] ThruLines Finds Your Common Ancestors TIDBIT (29 Jul 2019)

          [22AH] Help ThruLines by Adding Children and Grandchildren TIDBIT (29 Jul 2019)

          [22AI] ThruLines Has Xray Vision TIDBIT (29 Jul 2019)

          [22AJ] ThruLines Helps with Y-DNA and mtDNA TIDBIT (29 Jul 2019)

          [22AK] A Few ThruLines Are False, and Some Are Misleading (29 Jul 2019)

          [22AL] Add ThruLines Info Into Match Notes TIDBIT (29 Jul 2019)

          [22AM] Use Match Notes from ThruLines to Identify Clusters (29 Jul 2019)

          [22AN ] ThruLines and Clusters and Snowballs (29 Jul 2019) *

          [22AO] How Does ThruLines Work TIDBIT (1 Aug 2019)

          [22AP] Extending the MRCA of a TG through Clusters TIDBIT (18 Nov 2019)

          [22AR] AncestryDNA ThruLines Missing Out TIDBIT (26 Mar 2020)

          [22CF] ThruLine Levity (11 Feb 2024)

          [22CG] ThruLines Is Quick (25 Feb 2024)

          [22CH] ThruLines is Quick – Really Quick (28 Feb 2024)

          [22BZ] Consensus (6 Dec 2023)

          [22BW] Getting ThruLines to Work for Me TIDBIT (7 Jul 2023)

[35B] Genetic Genealogy Spreadsheets (7 Dec 2021)

          [35BA] Ancestor Spreadsheet (22 Dec 2021) (Edit 23 Dec 2021)

          [35BC] Common Ancestor Spreadsheet (19 Dec 2021) * [see also 15K]

          [35BD] TG Master Spreadsheet [not yet posted]

          [35BE] TG Summary Spreadsheet (22 Dec 2021)

[35C] AncestryDNA ProTools

          [22DF] ProTools 1 – My Take on Ancestry ProTools (29 Jun 2024)

          [22CK] ProTools 2 – A ProTools Epiphany… (2 Jul 2024)

          [22CL] ProTools 3 – True Cousins Don’t Always Match Each Other (5 Jul 2024)

          [22CLa] ProTools 4 – The Spreadsheet (5 Jul 2024)

          [22CM] ProTools 5 – Small Segments At Work (7 Jul 2024)

          [22CN] ProTools 6 – Watch Out… (11 Jul 2024)

          [22CO] ProTools 7 – What Is Your Plan of Action? (17 Jul 2024)

          [22CP] ProTools 8 – Group Process (19 Jul 2024)

          [22CQ] ProTools 9 – Build A Foundation (25 Jul 2024)

          [22CR] ProTools 10 – Branch Groups (12 Aug 2024)

          [22CS] ProTools 11 – Ways to Analyze Shared Matches of Matches (SMOM) cMs (28 Oct 2024)

          [22CT] ProTools 12 – The Jokes on me… heads up! (28 Oct 2024)

          [22CU] ProTools 13 – Status of Common Ancestor Spreadsheet (17 Nov 2024)

          [22CV] ProTools 14 – Jigsaw Puzzle (24 Nov 2024)

          [22CW] ProTools 15 – Shared Match Cluster Hints (25 Nov 2024)

          [22CX] ProTools 16 – Sacrilegious Genetic Genealogy (5 Dec 2024)

          [22CY] ProTools 17 – NPEs (8 Dec 2024)

          [22CZ] ProTools 18 – Family Group Sheets (10 Dec 2024)

          [22DA] ProTools 19 – Comments on Sacrilegious Genetic Genealogy (11 Dec 2024

          [22DB] ProTools 20 – A Plan and Some TIPS (1 Jan 2025)

          [22DC] ProTools 21 – Adding a GUESS (9 Jan 2025)

          [22DD] ProTools 22 – A Rant about Relationships (10 Jan 2025)

          [22DE] ProTools 23 – Integrating With Genealogy (31 Jan 2025)

          [22DF] ProTools 24 – Small Segment Stats (21 Feb 2025)

          [22DG] ProTools 25 – The Path Is Key (22 Feb 2025)

[35D] GEDmatch

          [21A] Why Upload to GEDmatch or FTDNA? (11 Jun 2015)

          [22T] First Time at GEDmatch TIDBIT (1 May 2018)

          [21B] Getting Started with GEDmatch (19 Sep 2017)

          [22G] Uploading to GEDmatch TIDBIT (19 Jan 2017)

[22] Segmentology TIDBITs

          [22K] Amount of DNA vs Number of Matches TIDBIT (17 May 2017)

          [22X] Shorthand ID for Triangulated Groups TIDBIT (2 Feb 2019)

          [22AW] Percent DNA vs Percent Matches TIDBIT (4 May 2021)

          [22BK] Review the Comments TIDBIT (13 Dec 2022)

          [22BM] Small Segments Needed for Distant Ancestors TIDBIT (6 Mar 2023)

          [22BP] Who Ya Gonna Call? (hint: NOT Ghostbusters!) TIDBIT (28 Apr 2023)

          [22BR] How to Define the Most Recent Common Ancestor TIDBIT (13 May 2023)

          [22BS] Does the DNA Come from the MRCA Father or Mother? TIDBIT (15 May 2023)

          [22BT] Using the Shared cM Project in Reverse TIDBIT (1 Jun 2023)

          [22BU] A Means To An End TIDBIT (11 Jun 2023)

APPENDIX

[99] Terms and Abbreviations

[99A] Anatomy of an IBS segment by Ann Turner  (2 Oct 2015)

[99B] Advanced Genetic Genealogy Book (6 Apr 2019)

[99C] Celebrating the First 25 years of Genetic Genealogy (29 Feb 2024)

[99D] MITx Class on DNA is Free (28 Jan 2025]