Genetics Practice Problems
BROOKDALE COMMUNITY COLLEGE
Genetics Practice Problems
1 In snapdragon plants, flower color is transmitted by incomplete dominance. If a red flowering plant mates with a pink flowering plant, what phenotypes are possible in their offspring? Show the phenotypic ratio also.
2 In humans, freckles are dominant to no freckles. If a male with no freckles mates with a female who is heterozygous for freckles, what is the probability of their child having freckles?
3 Cystic fibrosis is transmitted by recessive inheritance. When 2 carriers of the disease mate, what is the probability that they will have a child with the disease?
4 Colorblindness is a condition in humans transmitted by a sex-linked recessive gene. A woman whose father was colorblind and whose mother has normal vision with no family history of colorblindness, mates with a man who has normal vision. What percentage of the offspring born to this couple will be colorblind?
5 What percentage of the daughters born to the couple in question #4 will be carriers of the colorblind gene?
6 What percentage of the sons born to the couple in question #4 will be colorblind?
7 A female with type A blood mates with a male with type B blood. What genotypes are possible for the type A female parent and the type B male parent?
8 The first child born to the couple in question #7 has type O blood. What do we now know about each parent’s genotype?
9 What other phenotypes are possible among additional children the couple in question #7 may have?
10 Achondroplasia is transmitted by true dominance. When a heterozygous male mates with a homozygous recessive female, what is the probability that their first child will have achondroplasia?
Genetics Practice Problems
1 In snapdragon plants, flower color is transmitted by incomplete dominance. If a red flowering plant mates with a pink flowering plant, what phenotypes are possible in their offspring? Show the phenotypic ratio also.
2 In humans, freckles are dominant to no freckles. If a male with no freckles mates with a female who is heterozygous for freckles, what is the probability of their child having freckles?
3 Cystic fibrosis is transmitted by recessive inheritance. When 2 carriers of the disease mate, what is the probability that they will have a child with the disease?
4 Colorblindness is a condition in humans transmitted by a sex-linked recessive gene. A woman whose father was colorblind and whose mother has normal vision with no family history of colorblindness, mates with a man who has normal vision. What percentage of the offspring born to this couple will be colorblind?
5 What percentage of the daughters born to the couple in question #4 will be carriers of the colorblind gene?
6 What percentage of the sons born to the couple in question #4 will be colorblind?
7 A female with type A blood mates with a male with type B blood. What genotypes are possible for the type A female parent and the type B male parent?
8 The first child born to the couple in question #7 has type O blood. What do we now know about each parent’s genotype?
9 What other phenotypes are possible among additional children the couple in question #7 may have?
10 Achondroplasia is transmitted by true dominance. When a heterozygous male mates with a homozygous recessive female, what is the probability that their first child will have achondroplasia?