Question 1

Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. Which of the following would you then expect?

Accepted Answer

A)   that homeotic genes are selectively expressed over developmental time
B)   that a homeobox-containing gene has to be a developmental regulator
C)   that homeoboxes cannot be expressed in nonhomeotic genes
D)   that all organisms must have homeotic genes
E)   that all organisms must have homeobox-containing genes A

Question 2

Humans have 23 pairs of chromosomes. In contrast, chimpanzees have 24 pairs of chromosomes and lack any pair resembling the long human chromosome 2 pair; instead, chimpanzees have two pairs of medium-sized chromosomes. What is the most likely explanation for these differences in the human and chimpanzee genomes?

Accepted Answer

A)   The common ancestor of humans and chimpanzees had 24 pairs of chromosomes, and at some point in the human lineage, two chromosomes fused end to end, providing some selective advantage.
B)   The common ancestor of humans and chimpanzees had 23 pairs of chromosomes, but when chimpanzees evolved, one of the chromosomes broke in half.
C)   At some point in evolution, human ancestors and chimpanzee ancestors were able to mate and produce fertile offspring, making a new species.
D)   Chromosome breakage resulted in additional centromeres being made, allowing meiosis to proceed successfully.
E)   Transposable elements transferred significantly large segments of the chromosomes to new locations. A

Question 3

Use Figure 18.2 to answer the next few questions.
  Figure 18.2 shows a diagram of blocks of genes on human chromosome 16 and the locations of blocks of similar genes on four chromosomes of the mouse.
-The movement of these blocks suggests that

Accepted Answer

A)   during evolutionary time, these sequences have separated and have returned to their original positions.
B)   DNA sequences within these blocks have become increasingly divergent.
C)   sequences represented have duplicated at least three times.
D)   chromosomal translocations have moved blocks of sequences to other chromosomes.
E)   higher mammals have more convergence of gene sequences related in function. D

Question 4

Homeotic genes

Accepted Answer

A)   encode transcription factors that control the expression of genes responsible for specific anatomical structures.
B)   are found only in Drosophila and other arthropods.
C)   are the only genes that contain the homeobox domain.
D)   encode proteins that form anatomical structures in the fly.
E)   are responsible for differentiation in muscle cells.

Question 5

Which of the following can be duplicated in a genome?

Accepted Answer

A)   DNA sequences above a minimum size only
B)   DNA sequences below a minimum size only
C)   entire chromosomes only
D)   entire sets of chromosomes only
E)   sequences, chromosomes, or sets of chromosomes

Question 6

Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. These can now be used to

Accepted Answer

A)   introduce into relatives, such as elephants, certain mammoth traits.
B)   clone live woolly mammoths.
C)   study the relationships among woolly mammoths and other wool-producers.
D)   understand the evolutionary relationships among members of related taxa.
E)   appreciate the reasons why mammoths went extinct.

Question 7

What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting?

Accepted Answer

A)   The number of repeats varies widely from person to person or animal to animal.
B)   The sequence of DNA that is repeated varies significantly from individual to individual.
C)   The sequence variation is acted upon differently by natural selection in different environments.
D)   Every racial and ethnic group has inherited different short tandem repeats.

Question 8

A multigene family is composed of

Accepted Answer

A)   multiple genes whose products must be coordinately expressed.
B)   genes whose sequences are very similar and that probably arose by duplication.
C)   the many tandem repeats such as those found in centromeres and telomeres.
D)   a gene whose exons can be spliced in a number of different ways.
E)   a highly conserved gene found in a number of different species.

Question 9

What is proteomics?

Accepted Answer

A)   the linkage of each gene to a particular protein
B)   the study of the full protein set encoded by a genome
C)   the totality of the functional possibilities of a single protein
D)   the study of how amino acids are ordered in a protein
E)   the study of how a single gene activates many proteins

Question 10

Which of the following most correctly describes the whole-genome shotgun technique for sequencing a genome?

Accepted Answer

A)   genetic mapping followed immediately by sequencing
B)   physical mapping followed immediately by sequencing
C)   cloning large genome fragments into very large vectors such as YACs, followed by sequencing
D)   cloning fragments from many copies of an entire chromosome, sequencing the fragments, and then ordering the sequences
E)   cloning the whole genome directly, from one end to the other

Question 11

A microarray known as a GeneChip, with most of the human protein-coding genetic sequences, has been developed to aid in the study of human cancer by first comparing two to three subsets of cancer subtypes. What kind of information might be gleaned from this GeneChip to aid in cancer prevention?

Accepted Answer

A)   information about whether or not a patient has this type of cancer prior to treatment
B)   evidence that might suggest how best to treat a person's cancer with chemotherapy
C)   data that could alert patients to what kind of cancer they were likely to acquire
D)   information about which parent might have provided a patient with cancer-causing genes
E)   information on cancer epidemiology in the United States or elsewhere

Question 12

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?

Accepted Answer

A)   gene duplication
B)   alternative splicing
C)   exon shuffling
D)   histone modification
E)   random point mutations

Question 13

Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, so-called hemoglobin Lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?

Accepted Answer

A)   If it is still maintained in the human population, hemoglobin Lepore must be selected for in evolution.
B)   There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.
C)   Each of the genes in the hemoglobin gene family must show the same deletion.
D)   The deleted gene must have undergone exon shuffling.
E)   The deleted region must be located in a different area of the individual's genome.

Question 14

What is metagenomics?

Accepted Answer

A)   genomics as applied to a species that most typifies the average phenotype of its genus
B)   the sequence of one or two representative genes from several species
C)   the sequencing of only the most highly conserved genes in a lineage
D)   sequencing DNA from a group of species from the same ecosystem
E)   genomics as applied to an entire phylum

Question 15

When does exon shuffling occur?

Accepted Answer

A)   during splicing of DNA
B)   during DNA replication
C)   during meiotic recombination
D)   during post-translational modification of proteins
E)   during faulty DNA repair

Question 16

What is bioinformatics?

Accepted Answer

A)   a technique using 3-D images of genes to predict how and when they will be expressed
B)   the application of computational methods to the storage and analysis of biological data
C)   software programs available from NIH to design and synthesize genes
D)   a series of search programs that allow a student to identify which labs around the world are trying to sequence the genome of a given species
E)   a procedure that uses software to order DNA sequences in a variety of comparable ways

Question 17

Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this?

Accepted Answer

A)   exon shuffling
B)   intron activation
C)   pseudogene activation
D)   differential translation of mRNAs
E)   differential gene regulation over time

Question 18

Which procedure is not required when the shotgun approach to sequencing is modified as sequencing by synthesis, in which many small fragments are sequenced simultaneously?

Accepted Answer

A)   use of restriction enzymes
B)   sequencing each fragment
C)   cloning each fragment into a plasmid
D)   ordering the sequences
E)   PCR amplification

Question 19

A recent study compared the H. sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history. The data that suggested this were

Accepted Answer

A)   some Neanderthal sequences not found in humans.
B)   a number of modern H. sapiens with Neanderthal sequences.
C)   Neanderthal Y chromosomes preserved in the modern population of males.
D)   mitochondrial sequences common to both groups.

Question 20

One of the characteristics of retrotransposons is that

Accepted Answer

A)   they code for an enzyme that synthesizes DNA using an RNA template.
B)   they are found only in animal cells.
C)   they generally move by a cut-and-paste mechanism.
D)   they contribute a significant portion of the genetic variability seen within a population of gametes.
E)   their amplification is dependent on a retrovirus.

Exam 18: Genomes and Their Evolution