Final Answer:
1. b) autosomal recessive
2. Yes — both parents are carriers (heterozygous), so each child has a 25% chance of inheriting two recessive alleles and having the disease.
3. c) 25%
4. No — if only one parent is a carrier and the other is not affected and not a carrier, no child can inherit two recessive alleles, so none will have the disease.
5. d) X-linked recessive
6. Yes — the mother must be a carrier (since she has an affected son), and the father is unaffected, so each daughter has a 50% chance of being a carrier, and each son has a 50% chance of being affected.
7. c) 50%
8. No — because males have only one X chromosome, if they inherit the mutant allele, they will express the disease; females need two copies to be affected, which is rare in this pattern.
9. b) mitochondrial
10. Yes — mitochondrial DNA is inherited only from the mother, so all her children (sons and daughters) inherit her mitochondria and thus the mutation.
11. a) 100%
12. No — mitochondrial disorders affect energy production in cells, especially high-energy tissues like brain, muscle, and heart — not just one part of the body.
13. c) autosomal dominant
14. Yes — if one parent has the condition (and is heterozygous), each child has a 50% chance of inheriting the dominant allele and being affected.
15. b) 50%
Parent Tip: Review the logic above to help your child master the concept of pedigree chart worksheet.
