Law of segregation

• Gametes: 1:1 by F2
• Phenotype: 3:1
• Genotype: 1:2:1
• Test cross : Phenotype and genotype both are 1:1
• F1 produces : 1:1:1:1 gamete
• Phenotype: 9:3:3:1
• Genotype: 1:2:1:2:4:2:1:2:1
• Dihybrid: 27:9:9:9:3:3:3:1
• Complete dominance: 3:1
• Incomplete, co and overdominance: 1:2:1

Note:

a) Lethal: All die before reproduce usually recessive.

b) Semi lethal: 10% survive

c) Sub-vital: Some individual die

d) Vital: No effect on survival

e) Supra vital: Increased survival