Exam 4: Patterns of Inheritance

A baby boy is born with six toes (polydactyly)on his right foot,a trait that neither parent has but one that the paternal grandfather has.What is the best explanation for this occurrence?

What can be inferred about a genetic disorder that,when it occurs in monozygotic twins,affects one twin 80% of the time and affects both twins only 20% of the time?

Which statement about the X chromosome is true?

A man whose parents both have brown hair claims that his red beard was inherited from his maternal uncle.Why is this claim incorrect?

Which genetic disorder has both an autosomal dominant and an autosomal recessive form?

Why are dizygotic twins less likely to show concordance for a monogenic trait than monozygotic twins?

What is the most obvious expected finding when analyzing a four-generation pedigree for sex-linked dominant transmission of a trait?

Which common health problem has the highest heritability estimate?

Which type of genetic transmission promotes the continued existence of genetic mutations in single genes?

Which statement regarding inheritance of an autosomal dominant gene allele with known variability in expressivity is true?

Which statement or factor is a criterion for autosomal recessive transmission of single gene traits?

Which situation most closely represents an example of "regression to the mean?"

Which statement or condition best reflects multifactorial inheritance?

How does histone modification alter gene expression?

What is the significance of a shift to the left in the threshold value of liability in a threshold of liability model for the expression of a complex health problem with genetic influences?

In which situation are phenotype and genotype always the same?

Which statement reflects the criterion for autosomal dominant transmission of single gene traits?

Which person is an obligate carrier of an autosomal recessive single gene trait or disorder without expressing the trait or disorder?

What is the implication of the Agouti mice experiments with methylation?

A girl of normal stature is born to two parents with achondroplasia who have very short stature,especially disproportionately short arms and legs.What is the probability (by Punnett Square analysis)that any pregnancy this girl eventually has will result in the birth of an infant with achondroplasia if her partner also has normal stature?