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Kits, phasing & reconstruction

These are the power tools: they combine several kits, separate the DNA you got from each parent, and rebuild the DNA of ancestors who never tested.

The core idea. You inherit one of each parent's two chromosome copies at random. If you know enough relatives' DNA, you can work backwards and infer which alleles came from which grandparent — and even reconstruct an ancestor who is no longer alive to test.

🏷️ Tag Groups

IntermediateOpen tool

Assign tags to your kits and matches (e.g. "paternal", "Roma line", "to contact") and filter by them.

When to use it: When you are juggling many kits or matches and want to keep them organised.

How to use it
  1. Create a tag and apply it to kits or matches.
  2. Filter the match list by tag to focus on one branch or research thread.

🧰 Multiple Kit Analysis

IntermediateOpen tool

Compares several kits at once — useful for seeing how a group of relatives relate to one another and to a target kit.

When to use it: When you have tested several family members and want a combined view rather than one pair at a time.

🧬 Superkit

AdvancedOpen tool

Merges two or more of your own kits (for example an AncestryDNA and a 23andMe upload of the same person) into a single kit with more SNPs and better coverage.

When to use it: When you have tested the same person at more than one company and want one stronger kit for matching.

How to use it
  1. Select two or more of your own kits.
  2. Run the merge; positions are keyed by chromosome and position, missing calls are filled and conflicts are logged.
  3. The result is stored as a new kit (prefix SK) that you can use anywhere.

Reading the result:

  • A bigger shared SNP count with matches after merging (e.g. a parent–child pair can jump from ~186k to ~550k shared positions) is the sign it worked.
  • The conflict log lists positions where the source kits disagreed.
Keep in mind:
  • Only merge kits from the same person — merging different people creates nonsense.

➗ Phasing (both parents)

AdvancedOpen tool

Uses a child plus both parents to separate the child's DNA into its maternal and paternal halves, and to produce phased exports.

When to use it: When you have a child and both parents tested — this is the most accurate phasing possible and improves matching for everyone involved.

Reading the result:

  • Phased segments are assigned to the correct parent instead of being a mix.
  • The output can be exported and re-used as a phased kit.
Keep in mind:
  • A phased kit is only as good as the trio: a swapped or mislabelled parent will corrupt the result.

👀 Visual Phasing (siblings)

AdvancedOpen tool

Compares three or more siblings to work out which grandparent each shared segment came from, without needing the parents to be tested.

When to use it: When your parents are not available to test but you have several siblings.

How to use it
  1. Load three or more sibling kits.
  2. Follow the chromosome maps to assign segments to paternal and maternal grandparents.
Keep in mind:
  • You need at least three siblings, and the more the better — two siblings are not enough to resolve every region.

🧩 Reconstruct a parent (one-parent phasing)

AdvancedOpen tool

Phases a child against one tested parent to infer the alleles of the other parent, and stores them as that person's Tree DNA / virtual kit. The untested parent then works in matches, ThruLines and the chromosome browser.

When to use it: When one parent has tested and the other has not (or cannot), and you want the missing parent represented in the tree.

How to use it
  1. Pick the untested target person; the page suggests (child, known-parent) pairs.
  2. Run it as a background job and watch the live status.
  3. The virtual kit (prefix VK) is created and re-matched against the other kits.

Reading the result:

  • The child should then show a parent/child relationship to the reconstructed parent (about 3,400–3,600 cM).
  • Validation on known families gives over 99.9% concordance with the real genotypes.
Keep in mind:
  • Only the alleles that can be inferred from the child are recovered; the rest are left blank.
  • The X chromosome is only recovered for a female child.

✨ Lazarus

AdvancedOpen tool

Reconstructs an ancestor from several descendants who all match on the same segments, accumulating the shared alleles into a virtual kit for that ancestor.

When to use it: When an ancestor never tested but you have enough descendants whose DNA points to them.

Reading the result:

  • The reconstructed kit grows as more descendants and segments are added.
  • Conflicting positions are excluded and logged rather than silently overwritten.
Keep in mind:
  • A reconstruction is a partial, probabilistic picture — never treat a virtual kit as a real test.
  • If descendants come from both sides of a couple, you reconstruct the couple, not the individual.

Tested the same person twice?

Merge your duplicate kits into a Superkit for stronger matching.

Upload your raw DNA