Exam 15: Gene Mutation and Molecular Medicine

Suppose that a mutation appears in a small population of plants that changes the color of their seeds from yellow to green.This mutation reaches 100 percent frequency in the population.Many generations later, some individuals with yellow seeds are found.We can definitely say that these individuals have acquired a(n)

Which DNA analysis method measures DNA repeats?

A restriction enzyme cuts a 25,700 bp segment of DNA into three fragments: fragment A is 5,800 bp; fragment B is 6,600 bp; and fragment C is _______ bp.Fragment _______ will move the farthest in an electrophoresis gel.

_______ disease is caused by a single base substitution that changes one amino acid in a polypeptide.Phenotypic effects in homozygous individuals include defective, misshapen red blood cells.

Refer to the figure. The figure presents the data from individuals who have been tested for sickle-cell anemia using allele-specific oligonucleotide hybridization.The solid circles represent hybridization; the lined circles represent lack of hybridization.Which individuals have sickle-cell anemia?

In wild type Drosophila melanogaster, the order of genes on a chromosome is yellow, vermillion, forked, and Bobbed.Some of the flies have a different gene order: yellow, Bobbed, forked, and vermillion.The flies with the altered gene order most likely have a

Children born with two nonfunctional RB genes will develop retinoblastoma, a retinal tumor.The mutations that result in nonfunctional RB protein include the following types of mutations.Which mutation represents a SNP in the coding sequence of the gene?

The phenotypic effects of Duchenne muscle dystrophy vary considerably.This variation is explained largely by

A restriction enzyme cuts an 18,500 bp segment of DNA into three fragments.Fragment A is 4,400 bp and fragment B is 7,600 bp.Fragment C must be _______ bp.

A disease that is multifactorial is caused by

A researcher studying multi-coloration of Zea mays (maize) kernels compares the genomes of kernels that are red with those of kernels that are purple on the same corncob.The researcher examines the gene Zmf3′h1, whose functional expression results in red color instead of purple color.In the purple kernels, there is an insertion a few hundred base pairs long within this gene.When the researcher repeats this analysis of purple kernels on other corncobs, she sees the same phenomenon.However, the insertions occur at different points within the Zmf3′h1 gene.What genetic phenomenon has the researcher most likely found evidence of?

One parent is heterozygous for a certain known disease and is unaffected.The other parent is homozygous normal.Under which circumstance would DNA testing be of value for their newborn son to ensure he does not suffer complications due to the disease?

The isoenzyme hexosaminidase A (HEXA) is composed of subunits α and β and breaks down molecules containing terminal N-acetyl hexosamines.Tay-Sachs disease is caused by a recessively inherited loss-of-function mutation in the gene coding for the α subunit, which is the subunit that hydrolyzes the lipid GM2 ganglioside.Accumulation of this lipid in the brain leads to progressive deterioration of the nervous system and death, usually by age 4.The most common mutation in the HEXA gene is an insertion of four base pairs in exon 11 that creates a nonfunctional truncated protein.HEXA activity is 0 to 6 percent in homozygous recessives and 7 to 35 percent in heterozygous carriers, compared with noncarriers (100 percent).What evidence presented here strongly suggests that this truncated α subunit can still associate with the normal β subunit, thereby inhibiting its association with functional α subunit?

Frame-shift mutations occur

An insertion of _______ nucleotides would not cause a frame-shift mutation.

The essential application of DNA linkage mapping is to

For gene therapy to be most effective, genes should

Which disease is caused by interactions of multiple genes and the environment?

People with sickle-cell disease have abnormal

Adenosine deaminase (ADA) deficiency is a severe form of immunodeficiency that is usually fatal because of the greatly diminished ability of homozygous individuals to fight off bacterial and viral infections.The enzyme is necessary for the removal of the toxic metabolic product deoxyadenosine that is produced in T and B lymphocytes.Both T and B lymphocytes are produced by bone marrow stem cells, which can be harvested from patients.To restore T and B lymphocytes, a few children have been successfully treated for ADA with gene therapy, which would have been _______ gene therapy, given the above information.