Exam 4: Pedigree Analysis in Human Genetics

A child is born with a lethal dominant allele. This would seem to be impossible since either parent, had they possessed this allele, would have suffered its lethal effects. What is a possible explanation?

All genes are expressed in either the prenatal or newborn stages.

The frequency of heterozygotes for cystic fibrosis shows ethnic variations.

A missing or ineffective chlorine ion transporter is the cause of ____________________.

People with cystic fibrosis have difficulty digesting food properly.

Which one of the following is NOT usually a symptom of cystic fibrosis?

Camptodactyly

More than one mode of inheritance can be seen for a single trait.

Genetic diseases transmitted only by a mother to both sons and daughters result from ____________________ genes.

The phenotypes of a trait controlled by the same gene are not always identical.

Dystrophin is a protein that normally

The proportion of individuals in a population expressing a trait when they have the appropriate genotype represents the percent of ____________________ for the trait.

If Marfan syndrome results in death, it is usually due to rupture of the ____________________.

The basic method of genetic analysis in humans is ____________________ rather than experimental.

Parents with normal pigmentation have an albino child. What is the chance that their next child will have normal pigmentation?

Amal has a serious metabolic disorder known as PKU. His sister has the same disorder. Neither of Amal's parents have the disorder. What is the most likely inheritance pattern of this disorder?

If a pedigree of several generations shows only females affected by a particular trait, what can be ruled out?

Which of the following is a goal of pedigree analysis?

How do each of the following affect the expression of single gene traits: incomplete dominance, expressivity, penetrance?

If a man and his wife are affected with a dominant trait, then ____________________ of their children could be unaffected.