Exam 5: Patterns of Inheritance

Huntington's disease, an often fatal disease of the central nervous system, is inherited from a dominant allele. Furthermore, a person may not show symptoms of the disease until 30 - 50 years of age. Jack and Jill have been married for 40 years and have two children, Joe and Jane. Jack has recently been diagnosed with Huntington's disease. Assuming that Jane does not have the disease, determine the probability that one of the children will eventually have Huntington's. What is the probability that both Joe and Jane will inherit the disease?

You learned that the phenotypic ratio of the F₂ generation of a typical test cross was 3:1. The genotypic ratio was 1:2:1. Why is a different ratio seen in a dihybrid cross? What conditions must be met for these parameters to be true?

The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene

A gene on the X chromosome is said to be

The hairline of some people drops downward near the center of the forehead and forms a distinct point. This condition is known as widow's peak. The alternative phenotype is a continuous hairline that does not drop down. A person with widow's peak always has an affected parent. Explain the inheritance pattern of widow's peak.

The determination of gene positions on chromosomes is known as

The protein responsible for cystic fibrosis is

Gregor Mendel was successful in his analysis of the genetics of pea plants because

The defective protein that actually causes cystic fibrosis is found in

Explain the role of the human genome project and modern medicine in helping to find a cure for cystic fibrosis.

The ABO blood type gene is an example of ___________, which means that heterozygotes display two phenotypes at the same time.

A woman with type A blood just had her first child. The child, like mother, had type A blood. What are all of the possible blood types of the father?

Describe how you might analyze a pedigree to determine whether a particular condition is recessive or dominant, and X-linked or autosomal. For the sake of this question, ignore conditions such as multiple alleles, incomplete dominance, and other complications.

The physical characteristics of an organism resulting from its genes are known as the organism's

What is the probability that a person would have cystic fibrosis if one of her parents was homozygous dominant and the other was a carrier for cystic fibrosis?

Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of

Most cases of red-green colorblindness are inherited as an X-linked recessive characteristic. Which of the following are possible if a woman, who is a carrier for colorblindness, has offspring with a male who is colorblind?

With respect to genetic traits, what is the opposite of recessive?

Mendel correctly surmised that the 3 dominant:1 recessive phenotypic ratio seen in the F₂ generation pea plants was due to