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Matching & relationship tools

These are the tools you will use most. They compare your kit against the other kits on the site and tell you how closely you are related — and exactly which pieces of chromosome you share.

Two words to know. A centimorgan (cM) is a unit of genetic distance, not of DNA length — the more cM you share with someone, the closer the relationship. A segment is one unbroken run of shared DNA; close relatives share many cM in a few long segments, distant relatives share a little in many short ones. As a rough guide: parent/child ≈ 3,400–3,600 cM, full siblings ≈ 2,300–2,900 cM, first cousins ≈ 550–1,300 cM.
A third thing to know for Roma research: endogamy. Many Roma and Romani families married within the community for generations, so both of your parents can descend from the same ancestors. The result is that you share more DNA, in more segments, and often in double (IBD2) segments, with relatives who are actually quite distant. The relationship ranges used by every testing company assume an "outbred" family, so for Roma data they tend to read too close. Always interpret a cM total with endogamy in mind — and lean on the largest segment, triangulation and your tree rather than the cM figure alone.

📋 One-to-Many

BeginnerOpen tool

Compares one of your kits against every other kit it can see and lists the matches, closest first, with shared cM, number of segments and the largest segment.

When to use it: This is the first thing to run after uploading — it gives you the shortlist of people worth investigating.

How to use it
  1. Pick a kit (yours by default).
  2. Read the list from the top: the highest cM are your closest relatives.
  3. Click Review on a match for the full match page — relationship estimate, shared matches and a chromosome browser.
  4. Click Compare to run a detailed One-to-One against that match.

Reading the result:

  • Shared cM — the main closeness signal.
  • Segments — how many separate shared blocks.
  • Largest segment — the most useful column for distant matches; one big segment is stronger evidence than many tiny ones.
  • Relationship estimate — a ranked range (e.g. "2nd–3rd cousin") plus a SegcM percentage where available.
  • Same person (duplicate kit) — flagged automatically when a kit is effectively a duplicate of another.
Keep in mind:
  • Very small segments (under ~7 cM) are usually not evidence of a real relationship — the default minimum here is 6–7 cM.
  • Different testing chips overlap imperfectly, so a cross-company match can show slightly fewer cM than the same relationship tested on one company.

Pairs that have not been computed yet show a "still processing" note — this normally clears within a few minutes.

🔬 One-to-One Autosomal

BeginnerOpen tool

Compares two kits in detail and prints every shared segment (chromosome, start, stop, SNPs and cM), with an interactive chromosome browser that paints the shared blocks.

When to use it: When you want to confirm a match, see exactly where you share DNA, or check whether a suspected relationship is real.

How to use it
  1. Choose your kit and the other kit. The dropdown lists your own kits; to compare against anyone else, type their kit number (e.g. AN000003) in the box.
  2. Optionally raise the minimum cM to hide background segments.
  3. Submit and read the segment table; the chromosome browser shows the shared regions in green.

Reading the result:

  • Single (IBD1) segments are shared on one chromosome copy — the usual evidence of a relationship.
  • Double (IBD2) segments are shared on both chromosome copies — the same DNA came from both of your parents. In an outbred family that essentially only happens for full siblings (about 25% of the genome); a parent and child share one copy everywhere and have no double segments. In endogamous Roma families, where both parents often descend from the same community, double segments also appear between more distant cousins.
  • The total cM and segment count together decide how close the relationship is.
Keep in mind:
  • A parent/child pair shares DNA in one long "half-identical" stretch on every chromosome and no double segments; full siblings share a mix of single and double segments. That is the fastest way to tell those two apart — but in endogamous families double segments also show up between more distant relatives, so never rely on them alone.

🔎 Segment Search

IntermediateOpen tool

The one-to-many view of segments: instead of pair totals, it lists every shared segment your query kit has with every other kit — chromosome, start/stop, SNPs and cM.

When to use it: When you want to find everyone who shares a particular region of a chromosome, for example to build a triangulation group.

How to use it
  1. Choose the query kit.
  2. Optionally restrict to one or more chromosomes and a position range (any segment overlapping the range is kept).
  3. Run it and export the table to CSV for further analysis.

Reading the result:

  • Rows sharing an overlapping region are candidates for a common ancestor.
  • Sorting by chromosome and start position reveals clusters of matches over the same stretch.
Keep in mind:
  • A shared segment only proves a common ancestor when the same segment is shared by several people who also match each other — see Triangulation.

🔺 Triangulation

IntermediateOpen tool

Groups matches that all share the same chromosome region with you. A triangulated group is strong evidence that the shared segment came from one common ancestor.

When to use it: When you want to push a match back to a specific ancestral line, or split matches into paternal and maternal sides.

How to use it
  1. Choose a kit and a minimum cM.
  2. Review the clusters: each lists the members, the shared region and (where the tree has them) a common-ancestor column.
  3. Use Add all clusters to tree DNA to record the inferred segment against an ancestor in your tree.

Reading the result:

  • A cluster of three or more people who all overlap the same region and match each other is a triangulation group.
  • The common-ancestor column names the tree person the group is consistent with.
Keep in mind:
  • Endogamy and small reference populations can create "false" triangulation groups — always sanity-check against the tree and documentary evidence.

📊 Relationship Probability

BeginnerOpen tool

Turns a shared-cM figure (and optionally the number of segments, your ages and the match's sex) into ranked probabilities for every possible relationship, laid out on a DNA-Painter-style chart.

When to use it: When you have a cM total from any company and want to know what relationships are plausible — or rule some out.

How to use it
  1. Enter the shared cM (required) and the number of segments if you have it.
  2. Add your birth year and the match's birth year to prune relationships that the age gap makes impossible.
  3. Type in the cM box and watch the chart highlight the relationships whose range contains that value; the tables below rank them with percentages.

Reading the result:

  • The most likely summary names the top relationship(s).
  • The chart outlines the matching boxes; the top three are colour-coded gold/silver/bronze.
  • The "ruled out by age gap" list shows relationships the ages exclude.
Keep in mind:
  • Distributions overlap heavily: 1,200 cM could be a half-sibling, an aunt or a grandparent. Combine the cM with the tree and ages before concluding.
  • This tool uses the Shared cM Project 4.0 ranges, which explicitly assume no endogamy. In an endogamous Roma family the real relationship is usually more distant than the cM suggests, so treat these probabilities as an upper bound on closeness.

cM ranges: Shared cM Project 4.0 (Blaine T. Bettinger, CC 4.0); chart layout inspired by DNA Painter.

👫 Are Your Parents Related?

BeginnerOpen tool

Scans your own kit for long runs of homozygosity (ROH) — stretches where both copies of a chromosome carry the same DNA, which happens when your parents were related.

When to use it: Run it early, especially if matches seem to fall on both sides of your family or you are seeing unusually high cM totals. It tells you whether your match sorting will be complicated by endogamy or cousin marriage.

Reading the result:

  • No significant ROH → your parents were probably unrelated (or only very distantly).
  • Long ROH segments → your parents share an ancestor; note the total length and the largest block.
  • The total ROH length is an estimate of your inbreeding coefficient (F): roughly 6% (1/16) is what you would expect if your parents were first cousins.
Keep in mind:
  • In Roma and other endogamous communities, long ROH is common and expected — it reflects generations of marriage within the community, not necessarily a recent relationship between your parents.
  • ROH can also come from other causes, and small reference populations naturally produce some — treat it as a hint, not proof.

🔍 User Lookup

BeginnerOpen tool

Finds a kit by its kit number (e.g. AN000003) and shows its basic details and owner.

When to use it: When someone gives you a kit number and you want to jump straight to it, or to compare against it from another tool.

How to use it
  1. Type the kit number and search.
  2. Follow the links to view that kit's matches or start a comparison.

New to all this?

Work through the getting-started guide first — it explains raw DNA and how to upload.

Upload your raw DNA