3.4 – Inheritance

1.An allele for lactase persistence allows humans to digest milk as adults. People who lack this allele are lactose intolerant in adulthood. What is the pattern of inheritance?

2. A dominant autosomal allele for lactase persistence allows humans to digest milk as adults. People who lack this allele are lactose intolerant in adulthood. If J and K have a child L, what is the probability that L will be lactase persistent?

3. A child has blood group A. The father of the child has blood group B. What are the possible genotypes of the mother? I. IAIA II. IAIB III. IAi

4. Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is based on DNA sequences and the cladogram on the right is based on comparing protein sequences. What is the reason that cladograms based on DNA sequences are more reliable predictors of the phylogenetic relationship of species than cladograms based on protein sequences?

5. Some breeds of dogs are characterized by the presence of a melanistic mask, which is a darkening of the fur near the nose, as shown by the arrow in this photograph. Which outcome is matched with a valid conclusion if dogs that were pure breeding for melanistic masks were crossed with dogs without melanistic masks?

6. The diagram shows a pedigree of cystic fibrosis, in which the black colour indicates the presence of cystic fibrosis. The diagram shows a pedigree of cystic fibrosis, in which the black colour indicates the presence of cystic fibrosis.

7. The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive system. The graph shows the percentage of samples in which this bacterium showed resistance to six antibiotics over a period of ten years. What is a possible explanation for the total percentage resistance being larger than 100% in 2010?  

8. What proves that the inheritance of the condition shown in this pedigree chart is autosomal recessive and not autosomal dominant?

9. What is the major health issue resulting from the Chernobyl nuclear accident in 1986?

10. It is possible for two parents to have children with each of the four ABO blood groups. What blood groups would the parents have?

11. In a person who is heterozygous for sickle-cell anemia, where is the mutation found?

12. In a human with type A blood, what determines the blood group?

13. In a person who is heterozygous for sickle-cell anemia, where is the mutation found?

14. In a human with type A blood, what determines the blood group?

15. If a man with blood group O and a woman with blood group AB have children, which blood group(s) could the children have?

16. Which individuals are colour blind in this Punnett grid?  

17. The feather colour of a certain breed of chicken is controlled by codominant alleles. A cross between a homozygous black-feathered chicken and a homozygous white-feathered chicken produces all speckled chickens. What phenotypic ratios would be expected from a cross between two speckled chickens?

18. The presence of freckles is a characteristic controlled by a dominant gene. Two parents who are heterozygous for the characteristic have three children, all of whom have freckles. Which statement is true if they have a fourth child?  

19. What maximum number of different genotypes and phenotypes are possible among the children of a mother with blood group A and a father with blood group B?

20. What is the difference between dominant, recessive and codominant alleles?

21. Which genotypes are possible when a male with blood group AB and a female with blood group O have offspring?  

22. The following shows a pedigree chart. What type of inheritance is shown in this pedigree chart?

23. In guinea pigs black coat colour is dominant to white. In a test cross between a black and a white guinea pig both black and white offspring were produced. What percentage of the offspring would be expected to be white?  

24. What term describes the failure of sister chromatids to separate during anaphase II?  

25. In humans the ABO blood groups are an example of inheritance involving multiple alleles. In a family the parents have blood group A and blood group B respectively. Their first child has blood group O. What is the probability that their next child will have blood group B?

26. Alkaptonuria is an inherited condition in humans that affects phenylalanine and tyrosine metabolism, resulting in the production of black-coloured urine. What deduction can be made about the allele for this condition from the pedigree chart?

27. One type of gene mutation involves a base substitution. What are the consequences of the base substitutions in the two new sequences of DNA?

28. The diagram shows a pedigree. According to the pedigree shown, which pattern of inheritance is indicated?

29. If a father with A-type blood and a mother with B-type blood have a child, what is the probability that the child will have O-type blood?

30. What would be the expected result if a woman carrier for colour blindness and a colour blind man had many children?

31. In peas, tall is dominant to dwarf. In a cross between a dwarf plant and a heterozygous tall plant what percentage of the offspring will be dwarf?

32. Which of his grandparents must be a carrier if none of them had the disease?  

33. His wife does not carry the hemophilia allele. What would be expected in their children?

34. Which is a feature of sex-linked genes in humans?  

35. The Punnett grid shows the inheritance of blood groups. What is the ratio of phenotypes of the offspring?

36. A certain breed of mouse can have fur that is either black or brown. A mouse breeder performs a test cross using a brown mouse to determine the unknown genotype of a black mouse. There are four offspring produced by the cross. What conclusions can be drawn?

37. In humans a V-shaped hair line is dominant to a straight hair line. A woman with a V-shaped hair line and a man with a straight hair line have children. The woman has a mother with a straight hair line. What is the proportion of children who are likely to have a V-shaped hair line?  

38. A woman who is a carrier for hemophilia and a man who does not have hemophilia have a child. What is the probability that the child will have hemophilia?

39. Sickle-cell anemia is caused by a mutation. How many changes to the amino acid sequence are caused by this mutation?

40. A parent organism of unknown genotype is mated in a test cross. Half of the offspring have the same phenotype as the parent. What can be concluded from this result?

41. Rhesus factor is an antigen present on the surface of red blood cells of Rhesus positive individuals. Rhesus positive (Rh+ ) is dominant to Rhesus negative (Rh– ). A mother with Rhesus negative blood gives birth to a baby with Rhesus positive blood and there are concerns that subsequent pregnancies will trigger an immune response. What are the genotypes of the mother and her first baby?

42. The pedigree chart below shows the blood types of three members of a family. Which could be the blood types of individuals 1 and 2?

43. What type of inheritance is shown in this pedigree chart?

44. A man of blood group A and a woman of blood group B have a child. If both are heterozygous for the gene, what are the chances of them having a child with blood group B?

45. Which disease is an example of sex-linked (X-linked) inheritance?

46. Which of the following genotypes is possible in the offspring of a homozygous male with blood group A and a female with blood group B?

47. What is the cause of sickle-cell anemia?

48. The blood groups of a mother and four children are indicated on the pedigree chart below. What are the possible blood groups of the father?

49. Boys can inherit the recessive allele (c) that causes red-green colour blindness from their mother, not from their father. The allele for normal red and green vision is C. Which of the following genotypes are possible in men?  

50. If an organism that is homozygous recessive for a trait is crossed with a heterozygote, what is the chance of getting a homozygous recessive phenotype in the first generation?

51. Red-green colour blindness is a sex-linked condition. Which of the following always shows normal vision?

52. In a cross between red haired cattle and white haired cattle the offspring produced are always a colour called roan (light red). If the roan cattle are interbred they produce white, roan and red offspring. How many alleles are controlling this character?

53. What evidence is given in the pedigree chart below to prove that the condition is caused by a dominant allele?