Tools & Techniques

Shared cMs

The stats from Blaine Bettinger’s survey of actual shared DNA between known cousins

The interactive filter of the above for the amount shared you enter:

Chromosome painting

Paint which bits of DNA you inherited from which ancestors using chromosome map. Do watch the excellent video.

What are the odds (WATO)

Yet another great tool from DNA Painter.
Want to more easily figure out where a mystery might fit best into a known tree with a number of existing matches?

Summarising shared DNA – Maguire charts

Charting Companion produces some great charts for DNA.

Check out the DNA Matrix aka Maguire charts

Finding matches

WikiTree: Find any person of surname x where someone within 8 degrees of separation has indicated they have taken an atDNA test (substitute your SURNAME of choice – caps not necessary):


Automated clustering tools exist to take the hard yards out of grouping your matches into those likely to share the same branch of your ancestors

See RootsFinder, DNAGedCom, Genetic Affairs, GEDmatch (tier 1) in particular

All of which make the process much easier than this rather more labour intensive network technique:

A network technique documented by Shelly Crawford to show which of your matches connect to whom amongst your up to fourth cousin matches.
This technique utilizes the DNAGedCom client (small sub required) downloads of your ancestry match list and ICW files, and  the basic template from NodeXL (needs Excel 2007+and Windows)
Really helps target the messages to potential matches by showing their connections, and great for navigating between the connected ones.

My post about this – which has already found me a tested “cousin” on a branch of the tree I’ve long been trying to prove the fate of, and given me what seems to be a higher response rate to Ancestry messages.

Shelly’s more recent post about her successes with clustering – triangulation is the icing not the cake


Behold Genealogy: Double Match Triangulator
I particularly like his clear definition/distinction between

  • Double match
  • Triangulation
  • Full triangulation

For the mathematically minded interested in how many segments we inherit per ancestor and the numbers of resulting Triangulated Groups (TGs) – check out Jim Bartlett’s post on How many TGs from distant ancestors

See also TheLegalGenealogist’s blogpost about this new tool (Nov 2016).


  • Free tools
    Try the One to Many report for selected people and use the 3D chromosome browser option to see who all matches whom all else of your selection on which segment
  • Tier one tools (subscription)
    Use DNAGedcom’s instructions for the GEDMatch Matching Segment Search/Triangulation downloads to import the data for a kit from GEDmatch into DNAGedcom for use in the latter’s Autosomal DNA Segment Analyzer.
    Try the new (Nov 2016) Triangulation Groups which Jim Bartlett explained on the Rootsweb DNA list as:
    Think the way it works is like Tree branches: You are the trunk – everyone listed is a Match with you. Then some closer relatives are listed taking off from the trunk; then some smaller branches – taking off from the closer relatives (not the trunk) which form Triangulated Groups. Jim –
Blog posts:

Visual Phasing:

Phase your matches at FTDNA

You can import the result into DNAPainter which takes a lot of the work out of determining which are on the chromosome you inherited from your father (Paternal) and which on the chromosome you inherited from your mother (Maternal)

Check out their Family Matching FAQ for instructions

Tests or transfers:

It is recommended that you “fish in many ponds” to milk your DNA tests for as much as you can wring out of them.

Consider maximising your investment in DNA testing by uploading your DNA file to GEDMatch, and other companies accepting transfers.
This particularly applies if you have only tested at Ancestry as they do not provide the level of detail all the other companies do.
But (there’s always a but!) that does mean that you are not necessarily comparing like to like and have to bear in mind the differences when evaluating where it is best for you to re-test at another company and when to transfer.

My current conclusion is that if you have tested on Ancestry after they changed to their current chip (mid May 2016), it is  better to re-test at FamilyTreeDNA (their FamilyFinder test) than to transfer your Ancestry file to there but different populations will get different mileage on that.

MyHeritage accepts uploads from all companies, with a one-off fee per kit to unlock the tools beyond the basic match lists/contacts applying from mid Dec 2018

Those having problems converting a newer Ancestry file into FTDNA should explore this tool:

MyHeritage has massively improved their algorithms (Jan 2018 – and are a rapidly growing player in the market as well as adding an impressive (and growing) set of tools for working with your match lists.
Occasional posts on my DNA blog:

X Chr

Roberta Estes DNA-explained: X Marks the Spot
and the follow up: That Unruly X – Chromosome that is
Kitty Cooper: What does shared X DNA really mean

Working your DNA

From The DNA Geek:

Tools at Hapi-DNA to aid your analyses.