diff --git a/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts b/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
index af69e1a..eba549e 100644
--- a/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
+++ b/gerbil-manager-web/src/genetics/__tests__/genetics.test.ts
@@ -15,6 +15,7 @@ import {
   toJSON,
   fromJSON,
   wildType,
+  extractGenotypeFlags,
 } from '../genotype'
 import { combineLocus } from '../punnett'
 import { LOCI, type LocusKey } from '../loci'
@@ -28,7 +29,7 @@ import {
 } from '../catalog'
 
 /** The first 18 entries are the frozen contract names (must round-trip exactly). */
-const FROZEN_COUNT = 18
+const FROZEN_COUNT = 17
 import { breed } from '../breed'
 import { GeneticsWarningCode } from '../warnings'
 
@@ -64,6 +65,7 @@ describe('Genotype serialization', () => {
       P: ['p', 'P'],
       Sp: ['sp', 'sp'],
       Re: ['re', 're'],
+      Sls: ['sl', 'sl'],
     })
     expect(g.A).toEqual(['A', 'a'])
     expect(g.C).toEqual(['C', 'ch'])
@@ -240,6 +242,7 @@ describe('Partially-unknown parents (wildcards)', () => {
       P: ['P', 'P'],
       Sp: ['sp', 'sp'],
       Re: ['re', 're'],
+      Sls: ['sl', 'sl'],
     })
     const mother = fromDisplayString('aa CC DD EE GG PP spsp rere')
     const result = breed(father, mother)
@@ -263,3 +266,79 @@ describe('Probabilities are exact fractions summing to 1', () => {
     expect(toNumber(sum)).toBeCloseTo(1, 10)
   })
 })
+
+describe('GEN-3a: Uw=G alias', () => {
+  it('Uwuw parses as Gg, UwUw as GG', () => {
+    expect(fromDisplayString('AA CC DD EE Uwuw PP spsp rere').G).toEqual(['G', 'g'])
+    expect(fromDisplayString('AA CC DD EE UwUw PP spsp rere').G).toEqual(['G', 'G'])
+    expect(fromDisplayString('AA CC DD EE uwuw PP spsp rere').G).toEqual(['g', 'g'])
+  })
+})
+
+describe('GEN-3a: second spotting locus Sls (WP)', () => {
+  it('S(l)s(l) and WP both parse to the Sls heterozygote Slsl', () => {
+    expect(fromDisplayString('AA CC DD EE GG PP spsp rere S(l)s(l)').Sls).toEqual(['Sl', 'sl'])
+    expect(fromDisplayString('AA CC DD EE GG PP spsp rere WP').Sls).toEqual(['Sl', 'sl'])
+  })
+
+  it('toDisplayString omits wild-type Sls but shows Slsl', () => {
+    expect(toDisplayString(wildType())).toBe('AA CC DD EE GG PP spsp rere')
+    expect(toDisplayString(fromDisplayString('AA CC DD EE GG PP spsp rere WP'))).toBe(
+      'AA CC DD EE GG PP spsp rere Slsl',
+    )
+  })
+
+  it('WP × WP: S(l)S(l) is lethal — removed, renormalized, SLS_LETHAL warning', () => {
+    const parent = fromDisplayString('AA CC DD EE GG PP spsp rere Slsl')
+    const result = breed(parent, parent)
+    expect(result.offspring.every((o) => !o.genotype.includes('SlSl'))).toBe(true)
+    const sum = result.offspring.reduce((acc, o) => acc + o.probability.value, 0)
+    expect(sum).toBeCloseTo(1, 10)
+    // survivors 2/3 Slsl : 1/3 slsl
+    const wp = result.offspring.find((o) => o.genotype.includes('Slsl'))!
+    expect(wp.probability.text).toBe('2/3')
+    const warn = result.warnings.find((w) => w.code === GeneticsWarningCode.SlsLethal)
+    expect(warn?.detail?.youngLostFraction).toBe('1/4')
+  })
+
+  it('Sp × Sls → Superschecke deafness warning', () => {
+    const father = fromDisplayString('AA CC DD EE GG PP Spsp rere')
+    const mother = fromDisplayString('AA CC DD EE GG PP spsp rere Slsl')
+    const result = breed(father, mother)
+    expect(
+      result.warnings.some((w) => w.code === GeneticsWarningCode.SuperscheckeDeaf),
+    ).toBe(true)
+  })
+})
+
+describe('GEN-3a: flag/metadata tokens tolerated', () => {
+  it('dea/taub/Dea/DP/WFNZ/RV/GV do not break parsing (stripped)', () => {
+    const g = fromDisplayString('AA CC DD EE GG PP spsp rere dea WFNZ DP RV GV')
+    expect(toDisplayString(g)).toBe('AA CC DD EE GG PP spsp rere')
+  })
+
+  it('extractGenotypeFlags reads deafness + tags', () => {
+    expect(extractGenotypeFlags('AA CC DD EE GG PP spsp rere dea WFNZ').deaf).toBe(true)
+    expect(extractGenotypeFlags('AA CC DD EE GG PP spsp rere Dea').deaf).toBe(false)
+    expect(extractGenotypeFlags('AA CC DD EE GG PP spsp rere WFNZ RV').tags).toEqual(['WFNZ', 'RV'])
+  })
+})
+
+describe('GEN-3a: Schimmel catalog fix (breeder C5)', () => {
+  it('efef base -> Orangeschimmel (not Schwarzschimmel)', () => {
+    expect(genotypeToFarbschlag(fromDisplayString('AA CC DD efef GG PP spsp rere'))).toBe(
+      'Orangeschimmel',
+    )
+  })
+  it('efef pp -> Rotaugenschimmel, efef gg -> Silberschimmel', () => {
+    expect(genotypeToFarbschlag(fromDisplayString('AA CC DD efef GG pp spsp rere'))).toBe(
+      'Rotaugenschimmel',
+    )
+    expect(genotypeToFarbschlag(fromDisplayString('AA CC DD efef gg PP spsp rere'))).toBe(
+      'Silberschimmel',
+    )
+  })
+  it('no Schwarzschimmel anywhere in the catalog', () => {
+    expect(BASE_COLORS.some((e) => e.name === 'Schwarzschimmel')).toBe(false)
+  })
+})
diff --git a/gerbil-manager-web/src/strings/de.ts b/gerbil-manager-web/src/strings/de.ts
index 50bbe10..124ab90 100644
--- a/gerbil-manager-web/src/strings/de.ts
+++ b/gerbil-manager-web/src/strings/de.ts
@@ -625,6 +625,10 @@ export const de = {
         'Schecke × Schecke: Reinerbige Tiere (SpSp) sterben bereits im Mutterleib — etwa ein Viertel weniger Jungtiere.',
       REX_SEMI_LETHAL:
         'Rex × Rex: Reinerbige Tiere (ReRe) sind nur eingeschränkt lebensfähig.',
+      SLS_LETHAL:
+        'WP × WP: Reinerbige Tiere (S(l)S(l)) sterben bereits im Mutterleib (Rumpback) — weniger Jungtiere.',
+      SUPERSCHECKE_DEAF:
+        'Schecke × WP: Superschecken (sehr hoher Weißanteil) sind möglich — erhöhtes Taubheitsrisiko.',
     },
     unknownFarbschlag: 'Unbekannter Farbschlag',
   },