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Active Lecture Questions for
BIOLOGY, Eighth Edition
Neil Campbell & Jane Reece
Chapter 21
Genomes and Their Evolution
Questions prepared by
Jung Choi,
Georgia Institute of Technology
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Genome Sizes
Which species has the largest genome?
a) Homo sapiens
Craig Venter
b) African lungfish
b) African lungfish
Protopterus sp.Protopterus sp.
c) Lillium
a) Homo
sapiens
c)
Lillium
Craig Venter
d) Amoeba proteus
e) Podisma pedestris
d) Amoeba proteus
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
e) Podisma pedestris
Genome Sequencing
Which of these criteria have been used in selecting
species whose genomes have been sequenced?
a) The species should be relevant for human health or
well-being.
b) The species should have a relatively small genome.
c) The species should have an important ecological
role.
d) The species may yield key evolutionary insights.
e) The species is a well-studied model organism.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Genome Annotation and Gene Prediction
In sequencing the human genome (the first
vertebrate genome to be sequenced), how were
most protein-coding exons and genes identified and
annotated?
a) by identifying long open reading frames
b) by identifying DNA sequences that were conserved
in human, yeast, nematode, and fruit fly genomes
c) by mapping human mutations to the genomic DNA
sequence
d) by comparison to human cDNA and EST sequences
e) all of the above
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Comparative Genomics
On average, the human and chimpanzee DNA sequences
differ by 12 nucleotide substitutions per 1,000 base pairs
(bp). Fossil evidence suggests that the hominid lineage
diverged from the great apes 6 million years ago. Therefore,
a) the human lineage accumulated 2 mutations per
1,000 bp per million years.
b) a human protein-coding gene of 300 amino acids
evolved through an average of 12 mutation events.
c) the mutation rate for humans is 2 mutations per
1,000 bp per million years.
d) All of the above are true.
e) None of the above are true.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Human Evolution
Given the high degree of sequence similarity between the
human and chimpanzee genomes, what might be the most
important factor that drove hominid evolution in the past 6
million years?
a) small changes in proteins that affect their function or activity in
important ways
b) changes in regulatory sequences that affect the timing and
level of expression of genes
c) evolution of a few novel protein-coding genes that play key
roles in neural development
d) gene duplication events that selectively expanded a set of
genes favoring development of human traits
e) deletion of inactivation of genes that favor development of
primate traits
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Human Evolution Hypothesis Testing
What experimental technique could be used to test
the hypothesis that humans and chimpanzees have
significantly different patterns of gene expression?
a) comparison of promoter DNA sequences
b) hybridization of RNA from various human and
chimpanzee tissues to a DNA microarray containing
all 21,000 human genes
c) analysis of single nucleotide polymorphisms (SNPs)
in human and chimpanzee populations
d) comparison of human disease alleles to chimpanzee
homologues
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Transposons
The human genome has about 7,000 Alu elements not found
in chimpanzees, whereas the chimpanzee genome has about
2,300 Alu elements not found in humans. How might the
Alu elements influence human evolution?
a) They may affect levels of expression of adjacent
genes.
b) They may create new alternative splicing variants of
a protein.
c) They may promote recombination events that induce
chromosomal rearrangements, deletions, and
duplications.
d) all of the above
e) none of the above: Alu elements are “junk” DNA
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.
Pseudogenes
Many pseudogenes in vertebrate genomes lack introns.
What process may account for such pseudogenes?
a) gene duplication followed by DNA splicing to remove
introns
b) recombination between duplicated copies of genes
c) reverse transcription of a processed mRNA and
insertion of the cDNA copy to a new chromosomal
location
d) duplication events that involve just the exons
e) unequal crossing over between duplicated copies of
genes
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.