Biology XII: 5 Prin of Inher & Vari(3 Law of Segregation and Co

Law of Segregation and Co-dominance Co-dominance In co-dominance, the F1 progeny resembles both the parents. Example: ABO blood groups in human beings ABO blood groups are controlled by gene I. Gene I has three alleles, I A, I B and i. A person possesses any two of the three alleles. IA and I B dominate over i. But with each other, IA and IB are co-dominant. IA and I B contain A and B types of sugar, while i does not contain any sugar. Allele from Parent 1 Allele from Parent 2 Genotype of offspring Blood type of offspring I A I A I A I A A I A I B I A I B AB I A i I A i A I B I A I A I B AB I B I B I B I B B I B i I B i B i i i i O Multiple alleles: When more than two alleles control a character, as in human blood groups Multiple alleles are used in population studies.