1. The parents are heterozygous for the trait (Aa x Aa).
2. Each parent can produce two types of gametes: A or a.
3. The possible combinations of gametes from the parents are:
- A from father and A from mother → AA
- A from father and a from mother → Aa
- a from father and A from mother → Aa
- a from father and a from mother → aa
4. The genotypic ratio is 1 AA : 2 Aa : 1 aa.
5. The phenotypic ratio is 3 dominant phenotype : 1 recessive phenotype.
6. The probability of an offspring having the recessive phenotype (aa) is 1/4 or 25%.
7. The advantage of being in generation III is that it allows tracking of the trait across multiple generations, helping to identify carriers and predict inheritance patterns.
8. The genotype of individual III-1 is Aa (heterozygous carrier), as they do not express the recessive trait but have a child who does.
9. The genotype of individual III-2 is aa (homozygous recessive), as they express the recessive trait.
10. The genotype of individual II-2 is Aa (heterozygous carrier), as they have a child with the recessive trait but do not express it themselves.
11. The genotype of individual I-1 is Aa (heterozygous carrier), as they have a child with the recessive trait but do not express it themselves.
12. The genotype of individual I-2 is Aa (heterozygous carrier), as they have a child with the recessive trait but do not express it themselves.
Parent Tip: Review the logic above to help your child master the concept of amoeba sisters mutations worksheet answer key.
