Exam 15: Gene Mutation and Molecular Medicine

Linkage analysis is a type of reverse genetics that makes use of family genetic histories, or _______.

In families with the fragile-X chromosomal abnormality, males with a moderate number of triplet repeats are usually unaffected and are considered to be _______.

Describe the expected effects of a somatic cell mutation that results in the gain of function of an oncogene.

In _______ gene therapy, target cells are removed from the individual, given the new gene, and then reinserted into the individual.

Refer to the figure. Through the use of linkage analysis, a researcher has identified a candidate gene responsible for a novel neurological disease.To obtain enough sample for DNA fingerprinting, the researcher uses PCR to amplify the gene.From the parent's DNA, PCR amplifies one band.From the child's DNA, the same size band plus a second larger band is amplified.Based on the published sequence of the gene, the researcher knows that restriction enzyme A will cut the wild-type allele into two fragments.The fragment sizes identified by DNA gel electrophoresis are shown in the figure.What technique should the researcher next use to identify the nature of the mutation with certainty?

The infection of cells by the human immunodeficiency virus (HIV) requires the virus to bind to the cell surface molecule CD3 and a second coreceptor molecule, CCR5 or CXCR4.In Scandinavian populations a mutation in CCR5 results in functional loss of CCR5 expression and exists at an allelic frequency of about 10 to 18 percent.Homozygous loss-of-function carriers are protected from infection by HIV strains that bind CCR5, and this mutation is also believed to have been protective against smallpox infection.This CCR5 mutation is evidence that mutations

In the past, it was common for people with phenylketonuria (PKU) who were placed on a low-phenylalanine diet after birth to be allowed to return to a normal diet during their teenage years.Although the levels of phenylalanine in their blood were high, their brains were thought to be beyond the stage when they could be harmed.If a woman with PKU becomes pregnant, however, a problem arises.Typically, the fetus is heterozygous but is unable, at early stages of development, to metabolize the high levels of phenylalanine that arrive from the mother's blood.(a) Why is the fetus likely to be heterozygous? (b) What do you think would happen to the fetus during this "maternal PKU" situation? (c) What would be your advice to a woman with PKU who wants to have a child?

The Epstein-Barr virus is commonly communicated, and more than 90 percent of individuals in the world are believed to be infected with it.The virus is linked to the development of Burkitt's lymphoma, a type of cancer of B lymphocytes.To induce cancer, the virus must function as a _______ when it integrates into the DNA of a B lymphocyte.

Mutational "hot spots" often occur when a methyl group has been added to

During the winter months at a farm in a warm climate, wild geese commonly feed on the peanuts, corn kernels, and grains that are scattered across the fields.During one unusually wet hunting season, some game hunters are alarmed to find that the livers of some of the harvested geese are abnormally lumpy.A veterinarian diagnoses the lumps as tumors, most likely the consequence of _______ poisoning through their ingestion of moldy peanuts.

Refer to the figure. The figure shows a series of STRs (just for one locus) for a mother, a child, and three men who are all being considered as the possible biological father (A, B, and C).Suppose that, based on the data from this locus, only one of the three men could be ruled out as the father.What further testing would be performed to determine definitively who the father is?

Refer to the figure. The figure shows the STR patterns at a hypothetical locus in a family in which some individuals develop high cholesterol.Immediately below the STR patterns are the cholesterol levels of each corresponding individual.What inferences can we draw from these results?

Because of the redundancy in the genetic code, many mutations in the coding regions of genes are

In chronic myelogenous leukemia (CML), certain white blood cells undergo a gain-of-function mutation resulting in a totally new protein.This cancer-inducing protein has unregulated enzymatic activity that promotes cell division.Based on this information, which treatment option would be the best fit for CML?

In DNA fingerprinting,

Which enzyme is used by bacteria as a defense against bacteriophage?

Nitrites, a human-made preservative for meats, and aflatoxin, a natural product produced by the mold Aspergillus, are similar in that

Which disease involves an expanding triplet repeat?

Prenatal screening is much more feasible today, in part because very few cells are needed.What technology has been most responsible for the reduction in the number of cells required?

Why are fetuses with PKU usually symptom-free?