In Mendelian dihybrid cross, how many types of genotypes and phenotypes will be present?

Concept-

• Gregor Mendel conducted hybridization experiments on garden peas for seven years (1856-1863).
• A dihybrid cross describes a mating experiment between two organisms that are identically hybrid for two traits.
• A hybrid organism is one that is heterozygous, which means that carries two different alleles at a particular genetic position.
• Therefore, a dihybrid organism is one that is heterozygous at two different genetic loci.
• Gregor Mendel performed dihybrid crosses on pea plants and discovered a fundamental law of genetics called the Law of Independent Assortment.

Explanation-

• Mendel selected traits for dihybrid cross for his experiments-
  • Colour of cotyledons- Yellow (Y) and Green (y).
  • Seed shape - Round (R) and Wrinkled (r).

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• The phenotypic ratio produced is 9: 3: 3: 1.
• The genotypic ratio produced is 1: 2: 2: 4: 1: 2: 1: 2: 1.

Therefore the 9 types of genotype and 4 types of the phenotype are present in the mendelian dihybrid cross.

Additional Information

• Monohybrid Cross
  • Phenotypic ratio- 3: 1
  • Genotypic ratio- 1: 2: 1