# How to document lineage evidence (GB-ID evidence levels L0-L4)

> On GenetixBay every parentage statement is a claim with an evidence level: L0 unverified, L1 community reported with a source, L2 breeder reported, L3 documented by an accepted GB-DOC, L4 lab-confirmed by a genomic report consistent with the parent-child relationship. Breeders raise the level by attaching dated, original evidence and, where possible, by recording crosses on the platform as they happen.

- Canonical: https://genetixbay.com/knowledge/breeding/documenting-lineage-evidence.html
- Category: Breeding · Level: Breeder
- Evidence: Supported · Status: Draft: awaiting expert review
- Stage: Any stage · Systems: Any system
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Questions and answers

**How do I prove the lineage of my strain?** Prove a cannabis strain's lineage by treating 'A x B' as a claim and attaching the strongest evidence you have. For a new cross, register both parents as GenetixBay records and log the pollination event on the day. For an old line, collect dated first-hand sources. A genomic parentage report on parent and offspring samples is the strongest proof.

**What are GenetixBay evidence levels?** GenetixBay evidence levels rate a lineage claim from L0 to L4. L0 is an unverified name, L1 a sourced community report, L2 the certified breeder's own statement, L3 an archivist-accepted document from the time such as a catalogue, patent or [lab certificate](https://genetixbay.com/knowledge/glossary/coa.md), and L4 a genomic report consistent with the parent-child relationship. Records show the highest accepted level.

**What documents count as lineage evidence?** Documents that count as cannabis lineage evidence include dated original forum posts by the breeder, [photos](https://genetixbay.com/knowledge/glossary/photoperiod.md) of original packs or catalogues, breeder journals with dated photos, patents and [plant breeders' rights](https://genetixbay.com/knowledge/glossary/plant-variety-protection.md) filings, and genomic parentage reports. A lab certificate of analysis supports [chemotype](https://genetixbay.com/knowledge/glossary/chemotype.md) claims only, not parentage. A name on a menu or [seed shop](https://genetixbay.com/knowledge/glossary/seed-bank.md) page is weak evidence.

**How do I get my cross to L3 or L4?** To reach L3, submit a document from the time, such as an era catalogue, patent, breeders' rights filing or dated original post, as a GB-DOC for archivist review. To reach L4, send leaf samples from both parents and several offspring to a [genotyping](https://genetixbay.com/knowledge/glossary/genotyping.md) lab and attach a report showing the parent-child relationship is consistent for those specific samples.

**What is a witnessed lineage?** A witnessed lineage is a GenetixBay flag for crosses recorded as they happen: both parents exist as individual or cut records and the pollination event was logged on the platform at the time. That makes parentage machine-verifiable within the platform's records. It is a separate flag alongside the evidence level and does not replace L4 DNA confirmation.

**How are lineage disputes handled?** On GenetixBay, any member with reputation 25 or higher can dispute a lineage claim with a reason and evidence. The claimant has 14 days to respond, then a three-person panel rules the claim upheld, overturned or unresolved. Losing claims are marked disputed or superseded but never deleted, and there is one appeal.

**Short answer.** Treat "A x B" as a claim and attach the strongest evidence you have. A name alone is L0. A sourced community report is L1. The certified breeder's own statement is L2. An archivist-accepted document from the time (catalogue, dated post, patent, lab certificate) is L3. A genomic report consistent with the parent-child relationship is L4. Crosses recorded on GenetixBay as they happen carry a separate "witnessed" flag.

## What's happening

Cannabis lineage history is mostly oral. Genetic studies show names and reported ancestry often don't match the DNA [3]. GenetixBay doesn't try to declare one "true" story. It records each claim, who made it, the evidence attached and any conflicting claims, in an append-only history (platform spec §6) [1].

## The evidence ladder

| Level | Name | What it takes | Who can set it |
|---|---|---|---|
| L0 | Unverified | A name or anonymous assertion | Anyone |
| L1 | Community reported | A member's claim with a source: dated forum post, photo of an old pack | Rep ≥25 |
| L2 | Breeder reported | The certified breeder of the line asserts it | GB-BRD owner |
| L3 | Documented | A GB-DOC accepted by an archivist: era catalogue, patent, plant breeders' rights filing, lab certificate (for chemotype claims) | Archivist (rep ≥500 or staff) |
| L4 | Lab-confirmed | Genomic report attached, parent/child relationship consistent | Staff archivist with lab report as GB-DOC |

Rules to know [1]:
- A record shows the **highest accepted level**, with the **number of conflicting claims** beside it.
- Levels change only through events; nothing is deleted.
- A verified breeder account is shown separately from verified genetics. A certified breeder can still make an L2 claim that turns out wrong.
- **Witnessed lineage** (`witnessed=true`): when both parents are GB-IND/GB-CUT records and the `pollination` event is logged on the platform at the time, parentage is machine-verifiable within the platform's records. It is a distinct flag, not a substitute for L4 DNA confirmation.

## What makes good evidence

| Evidence | Strength | Notes |
|---|---|---|
| Name on a menu or seed shop page | Weak (L0-L1) | Copies spread errors |
| Dated original forum post by the breeder, at the time | L1-L3 depending on acceptance | Archive the page (snapshot) and record the URL and date |
| Photo of an original pack or catalogue | L1, L3 if accepted with provenance | Show date, batch, maker |
| Breeder's own journal with dated photos | L2, stronger if logged live | Live GenetixBay journals carry server timestamps |
| Patent or plant breeders' rights filing | L3 | Formal, dated public record |
| Lab certificate of analysis | L3 for chemotype claims only | Not evidence of parentage; labs vary [5] |
| Genomic parentage report | L4 | Must show consistency for the specific parent and child samples [2] |

## Step by step: documenting a new cross (BRD-510 practical)

1. **Before [pollinating](https://genetixbay.com/knowledge/glossary/pollination.md),** make sure both parents exist as GB-IND or GB-CUT records with photos.
2. **Log the `pollination` event** on the day: female ID, male ID, date, branch.
3. **Create the GB-BAT** at harvest: seed count, [feminised](https://genetixbay.com/knowledge/glossary/feminised-seed.md)/regular, storage.
4. **Attach tests** as GB-DOCs: [germination](https://genetixbay.com/knowledge/glossary/germination.md), sex check, chemotype.
5. **Register the GB-GEN** with LIN claims to the parents (L2 as a certified breeder, plus the witnessed flag).
6. **Optional L4:** send leaf samples from the parents and several offspring to a genotyping lab; attach the report.

## Step by step: documenting an old (heritage) line

1. Collect every source: dated posts, catalogues, magazine articles, interviews, pack photos.
2. Separate **first-hand** (the breeder, at the time) from **second-hand** (later retellings).
3. Submit each as a separate claim with its own evidence. Conflicting claims sit side by side.
4. Request archivist review for L3.
5. If living material exists, compare its DNA to other samples sold under the same name (see [genotyping](https://genetixbay.com/knowledge/breeding/genotyping-what-tests-prove.md)).

## Disputes

Any member with rep ≥25 can dispute a claim with a reason and evidence. The claimant has 14 days to respond; a three-person panel rules upheld, overturned or unresolved. Losing claims are marked disputed or superseded, never deleted, and there is one appeal [1].

## Common mistakes

- Treating a lab [THC](https://genetixbay.com/knowledge/glossary/thc.md) certificate as proof of parentage.
- Citing a seed shop's description of someone else's line.
- Uploading screenshots without URL and date.
- Raising your own line's level by repeating your own claim across accounts (this is a moderation offence).

## Evidence

- Claims-and-evidence structure: GenetixBay policy [1].
- DNA parentage analysis principles: *Established* [2].
- Mismatch between names and DNA: *Supported* [3].
- Naming and publication principles: *Established* [4].

## Sources

1. GenetixBay. GB-ID provenance model, 2026. https://genetixbay.com/how-it-works
2. Jones AG, Small CM, Paczolt KA, Ratterman NL. 2010. A practical guide to methods of parentage analysis. Molecular Ecology Resources 10(1):6-30. https://doi.org/10.1111/j.1755-0998.2009.02778.x
3. Schwabe AL, McGlaughlin ME. 2019. Genetic tools weed out misconceptions of strain reliability in Cannabis sativa: implications for a budding industry. Journal of Cannabis Research 1:3. https://doi.org/10.1186/s42238-019-0001-1
4. Brickell CD, et al. (eds). 2016. International Code of Nomenclature for Cultivated Plants, 9th edition. Scripta Horticulturae 18. ISHS. https://www.ishs.org/scripta-horticulturae/international-code-nomenclature-cultivated-plants-ninth-edition
5. Jikomes N, Zoorob M. 2018. The cannabinoid content of legal cannabis in Washington State varies systematically across testing facilities and popular consumer products. Scientific Reports 8:4519. https://doi.org/10.1038/s41598-018-22755-2