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Dihybrid Cross Probability:
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A dihybrid cross examines the inheritance of two different traits simultaneously. It follows Mendel's principle of independent assortment, where alleles for different traits are distributed independently of one another during gamete formation.
The calculator uses the probability formula for dihybrid crosses:
Where:
Explanation: A dihybrid cross between two heterozygous parents (AaBb × AaBb) produces 16 possible genotype combinations in the offspring. The probability of a particular genotype combination is the number of squares showing that combination divided by 16.
Details: The result shows both the fractional probability (out of 16) and the percentage probability. For example, 4/16 = 0.25 (25%) would indicate a 25% chance of that genotype combination appearing in the offspring.
Tips: Count how many squares in the dihybrid Punnett square show your desired genotype combination and enter that number (0-16). The calculator will compute the probability.
Q1: Why divide by 16?
A: A dihybrid cross between two heterozygotes produces 16 possible genotype combinations (4×4 Punnett square).
Q2: What's the 9:3:3:1 ratio?
A: This is the classic phenotypic ratio for dihybrid crosses: 9 with both dominant traits, 3 with each single dominant trait, and 1 with both recessive traits.
Q3: How is this different from monohybrid crosses?
A: Monohybrid crosses examine one trait (2×2 Punnett square with 4 outcomes), while dihybrid examine two traits simultaneously (4×4 with 16 outcomes).
Q4: When does independent assortment not apply?
A: When genes are linked (located close together on the same chromosome), they don't assort independently and the 16-box Punnett square doesn't apply.
Q5: Can this calculator handle more complex crosses?
A: No, this is specifically for the standard dihybrid cross between two heterozygotes (AaBb × AaBb).