The ABO blood group is controlled by three alleles, IAI^AIA, IB I^B\,IB and iii.
IA I^A\,IA and IB I^B\,IB are codominant. Both IA I^A\,IA and IB I^B\,IB are dominant over iii.
The table shows the genotypes of two parents.
| Parent | Genotype |
|---|---|
| 1 | IAIBI^A I^BIAIB |
| 2 | IAiI^A iIAi |
For each parent, give the blood group shown by the genotype in the table.
The gametes from both parents are shown in the table. One possible offspring genotype has been completed.
Give the three missing offspring genotypes.
| Gamete from Parent 2 / gamete from Parent 1 | IAI^AIA | IBI^BIB |
|---|---|---|
| IAI^AIA | IAIAI^A I^AIAIA | |
| iii |
Using the completed table, calculate the probability of an offspring having blood group A.
71 exam-style questions on Edexcel GCSE Biology 3.3 Inheritance, covering 3.3.1 Gregor Mendel and the basis of genetics, 3.3.2 Alleles and inherited characteristics, 3.3.3 Monohybrid inheritance, 3.3.4 Determination of sex at fertilisation, 3.3.5 Outcomes from monohybrid crosses, 3.3.6 Inheritance of ABO blood groups, 3.3.7 Inheritance of sex-linked disorders, and 3.3.8 Multiple genes and phenotypic features. Each one has a worked solution and a mark scheme showing where the marks go.