1. What is a Dihybrid Cross?

A dihybrid cross examines the inheritance of two different traits simultaneously. According to Mendel's laws, these traits assort independently, resulting in the classic 9:3:3:1 phenotypic ratio in the F2 generation when crossing heterozygous parents.

2. How Does the Calculator Work?

The calculator generates all possible gametes for each parent, creates a Punnett square of their combinations, then analyzes the resulting offspring:

For a dihybrid cross (AaBb × AaBb):

• Each parent produces 4 types of gametes (AB, Ab, aB, ab)
• The Punnett square has 16 boxes (4×4)
• Phenotypic ratio: 9 dominant/dominant : 3 dominant/recessive : 3 recessive/dominant : 1 recessive/recessive

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

Explanation: The ratio emerges from independent assortment:

• 9/16 show both dominant phenotypes
• 3/16 show dominant for trait1, recessive for trait2
• 3/16 show recessive for trait1, dominant for trait2
• 1/16 show both recessive phenotypes

4. Using the Calculator

Tips: Enter 4-letter genotypes for each parent (e.g., AaBb). Capital letters represent dominant alleles, lowercase recessive. Describe your traits for better interpretation.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between monohybrid and dihybrid crosses?
A: Monohybrid examines one trait (3:1 ratio), dihybrid examines two traits simultaneously (9:3:3:1 ratio).

Q2: Does this always produce a 9:3:3:1 ratio?
A: Only when crossing heterozygotes for both traits with independent assortment. Linked genes alter ratios.

Q3: How do I represent incomplete dominance?
A: Use different notation (e.g., A' for intermediate) and expect different ratios (1:2:1 becomes more complex).

Q4: What if my genes are on the same chromosome?
A: Linked genes don't assort independently, producing different ratios based on recombination frequency.

Q5: Can this calculator handle more than two traits?
A: No, this is specifically for dihybrid crosses. Trihybrid crosses would require a 8×8 Punnett square.