Biology 003 UVM Exam 3 questions
with complete solutions
"Pedigree" - correct answer ✔✔ Breeding records of animals or genealogical records for
humans
Genetic Pedigree Analysis - correct answer ✔✔ Extensive, includes multiple relatives and even
in-laws. Also information on individual’s phenotype
Reasons for Pedigree Analysis - correct answer ✔✔ 1. Determine if observed trait is inherited
vs. environmental
2. Explain "mode of inheritance" of allele of given genome (dominant vs recessive or autosomal
vs sex-linked)
3. Mode determined, council parents on "risk" of passing on given trait
4. "Gene Hunting" technique - newly inherited traits w/ some known characteristics
"Mode of Inheritance" - correct answer ✔✔ Dominant vs Recessive
Autosomal vs Sex-Linked
"Standard" Set of Pedigree Symbols - correct answer ✔✔ Males = Squares
Females = Circles
Affected Individuals = Filled symbols
Line Thru = Deceased
Double Lines connecting = Inbred mating
,Challenges of Pedigrees - correct answer ✔✔ 1. Collecting written records over several
generations
2. "affected" family's knowledge = limited/ partially accurate
3. Living relatives scattered across globe
4. Info / "recollections" = hazy
5. Phenotypic expression may vary (assigning affected vs non = difficult due to... a. mutant allele
b. genetic "background" c. environmental conditions
Pedigrees and Singles Genes - correct answer ✔✔ Pedigrees work best with traits controlled by
single gene. More than one gene makes it difficult to unravel "mode of inheritance" for multiple
genes
Autosomal Dominant Inheritance (Pedigree Principles) - correct answer ✔✔ 1. All affected
should have one affected parent
2. Males & Females affected about equally (#'s)
3. Both Males & Females transmit the trait
4. Most affected are heterozygous (...50% of offspring affected)
5. Two affected may have an unaffected child (two recessive genes)
6. Trait won't appear in children of two unaffected parents
7. Trait may be more severe/ lethal in homozygous state
Autosomal Dominant Inheritance (Examples) - correct answer ✔✔ Marfan Syndrome -
Connective Tissue Defect. Affected tend to be tall and weak jointed. Major hazard = Aorta may
rupture
Familial Hypercholesterolemia (FH) - defect in LDL receptor. LDL is a carrier (to cells) for
cholesterol. Symptom = excess cholesterol in blood. Can lead to heart attack/ cell death.
Homozygosity is routinely fatal.
, Autosomal Recessive Inheritance (Pedigree Principles) - correct answer ✔✔ 1. Trait expressed in
both sexes and transmitted by wither sex to both sexes
2. Most affected are children of unaffected
3. Mating between affected and unaffected usually yields all unaffected children
4. Both parents affected, all children affected
Autosomal Recessive Inheritance (Examples) - correct answer ✔✔ Cystic Fibrosis - defect in
gene that controls salt & water transport from cells. Common in caucasians.
Sickle Cell Anemia - defect in gene for hemoglobin (oxygen carrying molecule of blood).
X-Linked Dominant Inheritance (Pedigree Principles) - correct answer ✔✔ 1. No male to male
inheritance
2. All daughters of affected male are affected
3. Males typically more severely affected than Females
4. Expression is more variable in females
5. In general pop. there are twice as many affected females than males
X-Linked Dominant Inheritance (Example) - correct answer ✔✔ Hypophosphatemia - Rare, low
levels of phosphate in blood. Caused by defect in kidney transport system inhibiting retention of
phosphate. Poor growth of bones and teeth. No cure.
X-Linked Recessive (Pedigree Principles) - correct answer ✔✔ 1. Phenotypic expression more
common in males than females
2. Father - Son inheritance is never seen
3. Unaffected Mom & Unaffected Dad can pass on trait to 1/2 males and no females
4. "Carrier" females often have affected male relatives and/or carrier females ancestors
with complete solutions
"Pedigree" - correct answer ✔✔ Breeding records of animals or genealogical records for
humans
Genetic Pedigree Analysis - correct answer ✔✔ Extensive, includes multiple relatives and even
in-laws. Also information on individual’s phenotype
Reasons for Pedigree Analysis - correct answer ✔✔ 1. Determine if observed trait is inherited
vs. environmental
2. Explain "mode of inheritance" of allele of given genome (dominant vs recessive or autosomal
vs sex-linked)
3. Mode determined, council parents on "risk" of passing on given trait
4. "Gene Hunting" technique - newly inherited traits w/ some known characteristics
"Mode of Inheritance" - correct answer ✔✔ Dominant vs Recessive
Autosomal vs Sex-Linked
"Standard" Set of Pedigree Symbols - correct answer ✔✔ Males = Squares
Females = Circles
Affected Individuals = Filled symbols
Line Thru = Deceased
Double Lines connecting = Inbred mating
,Challenges of Pedigrees - correct answer ✔✔ 1. Collecting written records over several
generations
2. "affected" family's knowledge = limited/ partially accurate
3. Living relatives scattered across globe
4. Info / "recollections" = hazy
5. Phenotypic expression may vary (assigning affected vs non = difficult due to... a. mutant allele
b. genetic "background" c. environmental conditions
Pedigrees and Singles Genes - correct answer ✔✔ Pedigrees work best with traits controlled by
single gene. More than one gene makes it difficult to unravel "mode of inheritance" for multiple
genes
Autosomal Dominant Inheritance (Pedigree Principles) - correct answer ✔✔ 1. All affected
should have one affected parent
2. Males & Females affected about equally (#'s)
3. Both Males & Females transmit the trait
4. Most affected are heterozygous (...50% of offspring affected)
5. Two affected may have an unaffected child (two recessive genes)
6. Trait won't appear in children of two unaffected parents
7. Trait may be more severe/ lethal in homozygous state
Autosomal Dominant Inheritance (Examples) - correct answer ✔✔ Marfan Syndrome -
Connective Tissue Defect. Affected tend to be tall and weak jointed. Major hazard = Aorta may
rupture
Familial Hypercholesterolemia (FH) - defect in LDL receptor. LDL is a carrier (to cells) for
cholesterol. Symptom = excess cholesterol in blood. Can lead to heart attack/ cell death.
Homozygosity is routinely fatal.
, Autosomal Recessive Inheritance (Pedigree Principles) - correct answer ✔✔ 1. Trait expressed in
both sexes and transmitted by wither sex to both sexes
2. Most affected are children of unaffected
3. Mating between affected and unaffected usually yields all unaffected children
4. Both parents affected, all children affected
Autosomal Recessive Inheritance (Examples) - correct answer ✔✔ Cystic Fibrosis - defect in
gene that controls salt & water transport from cells. Common in caucasians.
Sickle Cell Anemia - defect in gene for hemoglobin (oxygen carrying molecule of blood).
X-Linked Dominant Inheritance (Pedigree Principles) - correct answer ✔✔ 1. No male to male
inheritance
2. All daughters of affected male are affected
3. Males typically more severely affected than Females
4. Expression is more variable in females
5. In general pop. there are twice as many affected females than males
X-Linked Dominant Inheritance (Example) - correct answer ✔✔ Hypophosphatemia - Rare, low
levels of phosphate in blood. Caused by defect in kidney transport system inhibiting retention of
phosphate. Poor growth of bones and teeth. No cure.
X-Linked Recessive (Pedigree Principles) - correct answer ✔✔ 1. Phenotypic expression more
common in males than females
2. Father - Son inheritance is never seen
3. Unaffected Mom & Unaffected Dad can pass on trait to 1/2 males and no females
4. "Carrier" females often have affected male relatives and/or carrier females ancestors
