Codominance Worksheet (Blood types) Name Human blood types are determined by genes that follow the CODOMINANCE pattern of inheritance. There are two dominant alleles (IA and IB ) and one recessive allele (i). Blood Type (Phenotype) Genotype Can donate blood to: Can receive blood from: O ii A,B,AB and O (universal donor) O AB IA IB O, AB A,B,AB and O (universal receiver) A IA IA or IA i AB, A O,A B IBIB or IAi AB,B O,B 1. Write the genotype for each person based on the description: a. b. c. d. e. f. g. 2. Homozygous for the “B” allele Heterozygous for the “A” allele Type O Type “A” and had a type “O” parent Type “AB” Blood can be donated to anybody Can only get blood from a type “O” donor __IB IB___ __IA i____ __ii____ __IA i____ __IA IB____ __ii____ __ii____ Pretend that Brad Pitt is homozygous for the type B allele, and Angelina Jolie is type “O.” What are all the possible blood types of their baby? IB IB i IBi IBi i IBi IBi 100% Type B 3. i Draw a Punnett square showing all the possible blood types for the offspring produced by a type “O” mother and an a Type “AB” father IA IB IAi IBi IAi i IBi Type A or B 4. Mrs. Clink is type “A” and Mr. Clink is type “O.” They have three children named Matthew, Mark, and Luke. Mark is type “O,” Matthew is type “A,” and Luke is type “AB.” Based on this information: a. Mr. Clink must have the genotype __ii____ b. Mrs. Clink must have the genotype __IA i____ because _____Mark______ has blood type ___O___ c. Luke cannot be the child of these parents because neither parent has the allele __B___. 5. Two parents think their baby was switched at the hospital. Its 1968, so DNA fingerprinting technology does not exist yet. The mother has blood type “O,” the father has blood type “AB,” and the baby has blood type “B.” a. Mother’s genotype: ___ii____ b. Father’s genotype: __IA IB_____ c. Baby’s genotype: __IB IB____ or __IB i______ d. Punnett square showing all possible genotypes for children produced by this couple IA IB i IAi IBi i IAi IBi A or B e. Was the baby switched? No, it does not seem to have switched. 6. Two other parents think their baby was switched at the hospital. The mother has blood type “A,” the father has blood type “B,” and the baby has blood type “AB.” a. Mother’s genotype: _IA IA______ or ___IA i_____ b. Father’s genotype: __IB IB_____ or ___IB i_____ c. Baby’s genotype: _IA IB_____ d. Punnett square that shows the baby’s genotype as a possibility: IA i IB IAIB IBi i IAi ii e. Was the baby switched? Not necessarily 7. Based on the information in this table, which man could not be the father of the baby? Justify your answer with a Punnett square. Name Blood Type Mother Type A Baby Type B Sammy the player Type O George the sleaze Type AB The waiter Type A The cable guy Type B Sammy or The Waiter SAMMY: IA i i A I i ii i A I i ii IA i IA IAIA IAi i IAIA IAi The Waiter: