Chapter 18
A rapid way for natural evolution to alter a protein-coding gene so it encodes a protein with a different structure and function is _____. (eText Concept 18.5) exon duplication and exon shuffling single nucleotide substitutions mutations in the regulatory sequence of a gene homologous recombination recombinant DNA
a
The highly conserved sequence element present within homeotic genes is called the _____. (eText Concept 18.6) homeobox bicoid ced-3 morphogen TATA box
a
What can be learned from comparing the genomes of distantly related species, such as yeast and humans, or plants and fruit flies? (eText Concept 18.6) Conserved genes provide insight into their evolutionary relationships. Genes found in humans but not in yeast provide insight into human evolution. Conserved genes indicate that they were transferred laterally from one species to the other. All of the listed responses are correct. None of the listed responses is correct.
a
Why might a dog genome sequencing project prove particularly informative, compared to other mammalian genomes? (eText Concept 18.6) Genetic variation between breeds may be linked to phenotypic variation. Dogs are more closely related to humans than other mammals. The dog genome is smaller than other mammalian genomes. The dog genome lacks transposons. Dogs have large brains and sophisticated communication abilities.
a
A gene family has been identified that has undergone extensive duplication in humans, but is present in only one or a few copies in other primates or other mammals. What experimental approaches could be used to determine the function of this gene and its significance in human evolution? (eText Concept 18.6) Reduce the number of copies of this gene in a human subject. Create knockout mice to determine their phenotype. Determine the timing and location of expression of these genes during embryonic development in fruit flies. Introduce these genes into yeast and study the phenotype of the resulting cells. All of the listed responses are correct.
b
Bioinformatics includes all of the following EXCEPT __________. using computer programs to align DNA sequences using molecular biology to combine DNA from two different sources in a test tube analyzing protein interactions in a species using mathematical tools to make sense of biological systems developing computer-based tools for genome analysis
b
Multigene families arise as a result of _____. (eText Concept 18.5) transformation errors during DNA replication and recombination RNA splicing protein degradation the action of restriction enzymes
b
Two eukaryotic proteins are identical except for one domain in each protein, and these two domains are completely different from each other. Which of the following processes is most likely to have contributed to this difference? histone modification alternative splicing exon shuffling random point mutations gene duplication
b
Why might active transposons be rare in natural populations? (eText Concept 18.5) Organisms do not wish to evolve new genes. Individuals with active transposons are usually eliminated by natural selection, because transposition events usually produce harmful mutations. Multiple copies of a transposon suppress each other. The immune system attacks active transposons as foreign invaders. Transposons have a dramatically higher rate of mutation.
b
Why might the number of genes in the genome underestimate the number of different proteins that an organism makes? (eText Concept 18.3) The genome rearranges its DNA so that different cells can make different proteins. Many genes undergo alternative splicing, so that different proteins with different exon combinations are produced from the same gene. Organisms take up foreign DNA and make proteins encoded by these foreign DNA molecules. All of the listed responses are correct. None of the listed responses is correct.
b
A group of scientists is attempting to sequence the Neanderthal genome with DNA extracted from Neanderthal bones. Information from this project might reveal _____. (eText Concept 18.6) whether Neanderthals had language ability whether Neanderthals are the same species as modern humans what genetic differences may be responsible for the superior abilities of modern humans to communicate and make more sophisticated tools why Neanderthals became extinct All of the listed responses are correct
c
An example of a systems biology experiment might be _____. (eText Concept 18.2) determining what gene mutation causes insulin resistance determining the normal biochemical function of the gene involved in insulin resistance determining how insulin resistance affects transcription of thousands of other genes in the genome comparing the insulin resistance gene in human, mouse, and chimpanzee genomes All of the listed responses are correct.
c
Detailed comparison of the human and chimpanzee genomes has revealed that _____. (eText Concept 18.6) human and chimpanzee genomes are so similar that they should be considered to be the same species most differences are in the form of single nucleotide substitutions most differences are in the form of chromosomal rearrangements chimpanzee transposons are different from human transposons chimpanzees have more chromosomes
c
Given that about 25% of the mammalian genome is associated with genes, including introns and regulatory sequence, what would be the approximate average length of DNA per gene, if the genome contained 20,000 genes? (eText Concept 18.4) 1,000 base pairs 10,000 base pairs 40,000 base pairs 20,000 base pairs 80,000 base pairs
c
The advantage of copy-number variants (CNVs) over SNPs in human genomic studies is that CNVs _____. (eText Concept 18.6) provide reliable information about human genetic diversity occur only in noncoding DNA, which generally mutates at a constant rate and is more informative in measuring the genetic variation among human populations occupy much longer stretches of DNA than SNPs, and are likely to have greater phenotypic consequences have revealed significant genetic diversity existing among different human populations at geographic locations both near and far apart are far greater in number but of equal size to SNPs
c
The molecular data indicate that the globin gene family _____. (eText Concept 18.5) has two distinct evolutionary lineages, originating from an ancestral alpha-globin gene and an ancestral beta-globin gene arose through convergent evolution, where genes of different ancestry become similar over time because they have the same function evolved from a common globin gene ancestor that gave rise to both alpha- and beta-globin genes, as well as myoglobin and plant leghemoglobin evolved from a common ancestor of the alpha- and beta-globin genes, but that myoglobin and leghemoglobin arose from a different ancestor evolved through exon duplication
c
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? histone modification gene duplication exon shuffling alternative splicing random point mutations
c
Who discovered "jumping genes" (transposons)? (eText Concept 18.4) Chase Tatum McClintock Crick Pauling
c
Chromosomal rearrangements may be important in evolution because _____. (eText Concept 18.5) offspring who inherit two differently arranged sets of chromosomes instantly become a new species chromosomal rearrangements caused the extinction of dinosaurs, thereby allowing mammals to become dominant chromosome rearrangements cause new genes to evolve chromosome rearrangements lead to gene duplication, thus generating a "spare" copy of the gene that is free to evolve and acquire a new function chromosome rearrangements may cause genetic diseases
d
NCBI provides _____. (eText Concept 18.2) BLAST a database of protein structures Genbank All of the listed responses are correct. None of the listed responses is correct.
d
The human genome is thought to contain about how many genes? (eText Concept 18.3) 1,000-2,000 4,000-6,000 13,000-15,000 20,000-25,000 100,000-110,000
d
What factor accounts most for the difference in genome size between vertebrates and prokaryotes? (eText Concept 18.3) Vertebrates have more protein-coding genes. Vertebrates have longer and more complex upstream regulatory sequences Vertebrates have more genes for functional RNA molecules. Vertebrates have more noncoding DNA sequences. All of the listed responses are correct.
d
Which of the following best describes the experimental evidence that the FOXP2 gene is vital to the normal development of vocalization in vertebrates and yet has evolved among different vertebrate lineages? (eText Concept 18.6) Replacing the FOXP2 gene in mice with the human form of the gene had a neutral effect on development of vocalization in mice. Knocking out one of the two FOX2P genes in mice and humans had no effect on the development of vocalization in either species. Replacing the mouse FOX2P gene with songbird versions of the gene caused the transgenic mice to vocalize like songbirds. Replacing the FOX2P gene in mice with a humanized version of the gene had no negative effects on the mice but did lead to the development of brain cells in neural circuits that are associated with speech development in humans. When scientists knocked out the FOXP2 gene in human subjects, they observed the development of severe speech and language impairment.
d
Although containing the same number of genes as the nematode genome, the human genome is thought to bear greater phenotypic diversity by means of _____. (eText Concept 18.3) post-translation addition of carbohydrates to polypeptides alternate splicing of RNA transcripts regulation of gene expression by miRNAs post-translational cleavage of a polypeptide into active forms All of the listed responses are correct.
e
Alu elements _____. (eText Concept 18.4) are found only in the human genome encode their own transposase make up nearly 50% of the human genome are present in all mammals are derived from or related to transposable elements
e
Homeotic genes __________. are responsible for differentiation in muscle cells encode proteins that form anatomical structures in the fly are the only genes that contain the homeobox domain are found only in Drosophila and other arthropods encode transcription factors that control the expression of genes responsible for specific anatomical structures
e
One of the characteristics of retrotransposons is that __________. they are found only in animal cells they generally move by a cut-and-paste mechanism they contribute a significant portion of the genetic variability seen within a population of gametes their amplification is dependent on a retrovirus they code for an enzyme that synthesizes DNA using an RNA template
e
Segments of eukaryotic DNA that can move from one site to another in the genome by means of an RNA intermediate are called _____. (eText Concept 18.4) alleles plasmids transposons introns retrotransposons
e
The similarity of the homeobox in many different kinds of organisms is evidence _____. (eText Concept 18.6) of convergent evolution of analogy that it is not responsive to natural selection of its recent origin of the common ancestry of different life-forms
e
Which of the following best describes the findings of the ENCODE pilot study that thoroughly studied the makeup of a 1% region of the human genome? (eText Concept 18.2) Most of the fraction was composed of protein-coding genes. Most of the fraction was composed of exon sequences of genes. Only 2% of the region was transcribed into RNA. Over 50% of the region was composed of transcription enhancer sequences. Over 90% of the region was transcribed into different types of RNA.
e