D3.2.17 (HL)—Dihybrid crosses
Dihybrid crosses track inheritance of two genes at once, using gamete combinations to predict offspring ratios in inheritance problems in inheritance problems.
- Syllabus
- First assessment 2025
- Objective
- D3.2.17
- Level
- HL
Exam analysis
Chance of appearing12%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–2
Common command terms
- Determine
- Identify
- State
- Explain
- Predict
Recent exam appearances
November 2025Paper2 ["HL"] · TZ36(a)[ 3 ]D3.2.17 (HL)—Dihybrid crosses
November 2024Paper2 ["HL"] · TZ03(b)(i)[ 2 ]D3.2.17 (HL)—Dihybrid crosses
November 2023Paper2 ["HL"] · TZ24(c)[ 1 ]D3.2.17 (HL)—Dihybrid crosses
November 2023Paper2 ["HL"] · TZ24(b)[ 3 ]D3.2.17 (HL)—Dihybrid crosses
November 2023Paper2 ["HL"] · TZ24(a)[ 1 ]D3.2.17 (HL)—Dihybrid crosses
Practice this objective
Coverage 2012–2025 · Updated 16 Jul 2026
Concept essentials
- A dihybrid cross follows two genes simultaneously.
- Independent assortment creates different gamete combinations for unlinked genes.
- The 9:3:3:1 ratio applies only to particular heterozygous unlinked crosses.