1. What is a Dihybrid Cross?

A dihybrid cross is a breeding experiment between two organisms that are identical hybrids for two traits. This cross examines the inheritance of two different traits simultaneously, following Mendel's principle of independent assortment.

2. How Does the Calculator Work?

The calculator generates a Punnett square for two traits:

Where:

• 9 — Dominant for both traits
• 3 — Dominant for first trait, recessive for second
• 3 — Recessive for first trait, dominant for second
• 1 — Recessive for both traits

Explanation: The 9:3:3:1 ratio appears when two heterozygous parents (AaBb) are crossed, assuming independent assortment and complete dominance.

3. Understanding the 9:3:3:1 Ratio

Details: This classic ratio demonstrates Mendel's law of independent assortment, showing that alleles for different traits are distributed independently of one another during gamete formation.

4. Using the Calculator

Tips: Enter genotypes for both parents using 4 letters (e.g., AaBb). The calculator will show the possible offspring genotypes and the expected phenotypic ratio.

5. Frequently Asked Questions (FAQ)

Q1: What does the 9:3:3:1 ratio represent?
A: It represents the expected phenotypic ratio from a dihybrid cross between two heterozygous parents (9 dominant for both traits, 3 dominant/recessive, 3 recessive/dominant, 1 recessive for both).

Q2: When does this ratio not apply?
A: When genes are linked (on the same chromosome) or when there's incomplete dominance, codominance, or epistasis.

Q3: How many squares are in a dihybrid Punnett square?
A: 16 squares, representing all possible combinations of gametes from both parents.

Q4: What's the genotypic ratio for a dihybrid cross?
A: 1:2:1:2:4:2:1:2:1 for AABB:AABb:AAbb:AaBB:AaBb:Aabb:aaBB:aaBb:aabb.

Q5: Can I use this for trihybrid crosses?
A: No, this calculator is specifically for dihybrid crosses (two traits). Trihybrid crosses would require a 64-square Punnett square.