Deck 24: Genome Evolution

Question 1

If a gene is found in different groups,it is said to be

A)active.
B)variable.
C)conserved.
D)associational.
E)endogenous.

Answer 1

C

Question 2

Choose the true statement about the human genome and the tiger pufferfish genomes.

A)Essentially all the human genes have nearly identical counterparts in pufferfish.
B)The order of genes along the chromosomes in both species is essentially identical.
C)Both species have about the same amount of introns and "nonsense" sequences of DNA.
D)About 25% of human genes are unique when compared to the tiger pufferfish genome.

Answer 2

D

Question 3

One of the ways that two species can be compared,and information about the genetic basis of human diseases extracted,is by using their sequenced genomes and

A)looking at the allelic differences.
B)investigating the introns.
C)looking at the conserved sequences.
D)exchanging genomic information between them.

Answer 3

C

Question 4

Genome sequencing of the parasitic protist Plasmodium falciparum has been completed.One of the results is

A)Plasmodium is highly genetically similar to its host,Anopheles.
B)Plasmodium is highly genetically similar to its host,Drosophila.
C)Plasmodium has a chloroplast-like apicoplast that could be targeted by drugs.
D)Plasmodium produces fatty acids that are similar to ones found in humans and could be targeted by drugs.

Question 5

Genes are found in the same order for large stretches of the X chromosome in the rat and mouse genomes,indicating

A)occurrence of aneuploidy.
B)formation of pseudogenes.
C)conservation of synteny.
D)conservation of neoteny.

Question 6

Over long segments of chromosomes,the linear order of mouse and human genes is preserved.This is called conserved ________.

Question 7

Many retroviral-like transposons found in the human genome may have been transferred from viruses to mammals via ________ gene transfer.

Question 8

One of the unexpected findings to occur in comparing mouse and human genomes is

A)that "junk" DNA may be more functional than we assumed.
B)how incredibly different they are.
C)that there is far more "junk" DNA than we ever thought.
D)how similar some gene families are to their original transposons.

Question 9

The entire DNA sequence of a species is called its ________.

Question 10

The protein-coding gene sequences in humans and chimpanzees

A)are vastly different.
B)are about 50% alike.
C)are about 80% alike.
D)are more than 99% alike.
E)are identical.

Question 11

One of the reasons that pufferfish are a good species to compare to humans is because

A)it is so easy to hybridize the two and investigate the consequences.
B)they are so distantly related that it's easy to distinguish mutually conserved sequences.
C)the introns are often identical.
D)of the rapid response time in pufferfish to artificial selection.
E)they have been separated for so many millions of years and yet the gene sequence is almost identical.

Question 12

The breast cancer gene BRCA1 has a very similar sequence in humans,mice,and gorillas,due to its origination in a common ancestor.The BRCA1 genes in these species are examples of ________.

A)orthologs
B)paralogs
C)polyploidy
D)synteny

Question 13

Genes that have DNA sequences similar to functional genes but that do not appear to produce any functional product are ________.

Question 14

Two genes within an organism that arose from the duplication of a single gene in an ancestor are ________.

Question 15

In plants,________ induces elimination of duplicated genes.

Question 16

The best explanation for the phenotypic differences between humans and chimps despite the great similarities in their gene-coding sequences is

A)the vast differences in exons between their genomes.
B)the vast differences in the introns between their genomes.
C)the "junk" DNA of humans contains important sequences not present in chimps.
D)differences in gene expression between species.

Question 17

Duplication of individual chromosomes instead of whole genomes can occur by ________.

Question 18

Comparisons of human and mouse genomes reveals

A)they have widely different numbers of genes,and share only a few more genes than humans and pufferfish.
B)the differences between humans and mice are mainly the introns.
C)they have very little in common.
D)the genomes are very similar,with most of the genes unique to mice linked to size and shape.
E)the genomes are very similar,with most of the genes unique to mice linked to smell and reproduction.

Question 19

Except in rare cases,genes are usually passed from generation to generation within a species.This process is called:

A)horizontal gene transfer
B)vertical gene transfer
C)transgenesis
D)synteny

Question 20

Using the sequencing results for genomes from each of the kingdoms,it is currently possible

A)to explore genetic differences between species very directly,examining DNA changes.
B)to build,from scratch,complex organisms with trans-kingdom genomes.
C)to sequence and build,from scratch,simple organisms with trans-kingdom genomes.
D)to design humans with a variety of inter-kingdom abilities built into their DNA.

Question 21

Choose the correct sequence of events involving allopolyploidy that gave rise to modern tobacco.

A)hybridization,chromosome doubling,duplicate gene loss
B)hybridization,duplicate gene loss,chromosome doubling
C)chromosome doubling,hybridization,duplicate gene loss
D)duplicate gene loss,hybridization,chromosome doubling

Question 22

Choose the true statement about foreign DNA in the human genome.

A)Most of the foreign DNA in the human genome is ancient.
B)Most of the foreign DNA in the human genome is coding DNA.
C)Like the Drosophila genome,the human genome is constantly eliminating its foreign DNA.
D)New foreign DNA is regularly entering the human genome.

Question 23

Many genes in the human genome are no longer expressed because mutations have introduced stop codons within the coding sequence or transposons have disrupted gene function.These genes are now considered

A)pseudogenes.
B)orthologs.
C)paralogs.
D)homologues.

Question 24

Choose the true statements about the human and mouse genomes.

A)The human genome shares 99% of its genes with the mouse genome.
B)A comparison of genomes confirms that mice and humans shared a common ancestry more recently than humans and pufferfish.
C)Very few genes are conserved in the two genomes.
D)Little rearrangement of genes has occurred in the two genomes.

Question 25

Choose the most influential contributing factor to the reduced sense of smell in humans compared with the other great apes.

A)pseudogenes
B)conservation of synteny
C)aneuploidy
D)one more chromosome in humans compared to the other great apes
E)number of olfactory receptor (OR)genes present in the genome

Question 26

When a segment of DNA duplicates,causing two copies of a gene to be present in the chromosome,the duplicate copy could possibly (Check all that apply)

A)lose function due to mutation.
B)become an ortholog.
C)gain a new function due to mutation.
D)become a pseudogene.
E)become a centromere.

Question 27

Choose the true statements about orthologs and paralogs.

A)Orthologs are likely to have the same function.
B)Both orthologs and paralogs result from gene duplication.
C)The sequence of an ortholog is more likely to be conserved than the sequence of a paraloge.
D)Paralogs are more likely to be pseudogenes than are orthologs.
E)Paralogs often evolve new functions.

Question 28

The human genome

A)has no foreign DNA because it is excised by DNase.
B)has a very small amount of foreign DNA,mostly in the end caps (telomeres)of chromosomes.
C)has a lot of foreign DNA,mostly in the end caps (telomeres)of chromosomes.
D)has a lot of foreign DNA scattered throughout the genome,including transposons.

Question 29

Some of the olfactory receptor (OR)genes in humans

A)have been inactivated,reducing our olfactory capabilities compared to other primates.
B)have been activated,enhancing our olfactory sense compared to other primates.
C)have duplicated more frequently,resulting in increased paralogs compared to other primates.
D)have been conserved more rigidly,resulting in increased orthologs compared to other primates.

Question 30

Choose the true statement about the role of polyploidization in the evolution of plant genomes.

A)Jumping of transposons is most common many generations after a polyploidization event.
B)Genome downsizing following allopolyploidy usually affects the participating hybrids equally.
C)Genome downsizing following allopolyploidy results mainly from duplicate gene loss.
D)Crop plants rarely show evidence of polyploidization events.

Question 31

Choose the true statements about the human and tiger pufferfish genomes.

A)Genes regulating the basic cellular metabolism are conserved in both human and pufferfish genomes.
B)About 25% of the human genes have no counterpart in the pufferfish genome.
C)Being ancestral to humans,the pufferfish genome has more repetitive DNA than the human genome does.
D)The pufferfish genome has twice the amount of DNA as the human genome does.

Question 32

Gene inactivation is likely to produce

A)pseudogenes.
B)orthologs.
C)paralogs.
D)homologues.
E)horizontal gene transfer (HGT).

Question 33

The genomes of Arabidopsis thaliana,a small member of the mustard family of plants,and rice,Oryza sativa,have been sequenced.The findings include

A)the genome for each is almost identical,indicating that they diverged in the fairly recent past.
B)they each have very high copy numbers (slightly divergent copies of a gene),probably indicating episodes of polyploidy and/or segmental duplication.
C)repetitive DNA,including retrotransposons,was a very small proportion of both genomes.
D)more than 90% of the genes in each were particular to plants and not found in animal or fungal genomes.

Question 34

Which one of the following statements about horizontal gene transfer is false?

A)Horizontal gene transfer is also called lateral gene transfer.
B)Horizontal gene transfer involves hitchhiking genes from other species.
C)Horizontal gene transfer was common early in life,but is absent today.
D)Gene swapping is evident in the human genome.
E)The products of horizontal gene transfer often exist as transposons.

Question 35

Choose the true statements about duplicate genes.

A)Duplicate genes may retain their ancestral function by their resistance to mutation.
B)Duplicate genes can gain a derived function through subsequent mutation.
C)Gene duplication rarely occurs in growth and development genes,immune system genes,and cell-surface receptor genes.
D)Duplicate genes often share the same pattern of gene expression.

Question 36

Choose the true statements about the human and chimpanzee genomes.

A)A comparison of genomes confirms that humans and chimpanzees are closely related species.
B)Very few mutations differentiating the two genomes occur in coding DNA.
C)Some insertion-deletions (indels)lead to loss of function changes in the two genomes.
D)More similarity exists between the genomes of human and mouse than between human and chimpanzee.
E)The estimated genome sizes and number of genes is very different in humans and chimpanzees.

Question 37

Choose the true statements about the genomes of plants (especially Arabidopsis and rice),animals,and fungi.

A)Plants,animals,and fungi share most of the same genes for intermediary metabolism,genome replication,and protein synthesis.
B)"Plant" genes include those coding for photosynthetic pathways and morphology.
C)Plants generally have smaller genomes than those of animals and fungi.
D)Rice has fewer genes than humans.

Question 38

The types of human genes most likely to be duplicated,resulting in multiple copies,are

A)genes controlling basic tissue development.
B)immune system genes.
C)genes for cell surface receptors.
D)genes for controlling basic metabolism.

Question 39

Today,gene swapping between two species is

A)impossible,but it happened frequently in the distant past.
B)infrequent but possible; it happened more often in the distant past.
C)much more frequent compared to in the distant past.
D)only possible if they are in the same family of organisms,such as lions and tigers.

Question 40

Choose the true statement about synteny.

A)Synteny refers to the conservation of gene order along chromosomes.
B)Synteny refers to the constancy of chromosome numbers in related clades.
C)Synteny results from polyploidization events.
D)Synteny refers to the rearrangement of gene order due to inversions.
E)Synteny is only observed in closely related clades.

Question 41

Crop sunflowers are attacked by many fungal pathogens,such as downy mildew and Sclerotinia,resulting in economic losses of millions of dollars per year.What genes would be best to target for the development of new fungus-killing crop treatments (fungicides)?

A)Genes encoding chitin proteins that are shared by downy mildew and Sclerotinia,but absent in sunflower and humans.
B)Genes encoding growth proteins that are shared by downy mildew,Sclerotinia,and sunflower,but absent in humans.
C)Genes encoding metabolite proteins that are shared by downy mildew,Sclerotinia,and humans,but absent in sunflower.
D)Genes encoding basic development proteins that are shared by downy mildew,Sclerotinia,sunflower,and humans.

Question 42

During meiosis,a hexaploid hybrid spontaneously eliminates one set of chromosomes (eliminates 1n).What is the most likely result of this deletion?

A)The hybrid will no longer be able to reproduce.
B)The hybrid will be able to reproduce with one of the parental species.
C)The hybrid will no longer be polyploid.
D)The hybrid will be able to reproduce only by self-fertilization.

Question 43

The best explanation for why a mouse develops into a mouse and not a human is

A)most of the coding genes are different.
B)most of the non-coding genes are different.
C)gene expression differs.
D)the genes are mostly the same but have been rearranged.
E)synteny has not been conserved.

Question 44

How can analysis of mammalian genomes be used to detect and treat human disease? Check all that apply.

A)The genomes of the mammalian relatives of humans are the best targets for discovering new treatments for human diseases.
B)Comparing the genomes of parasite and host is likely to reveal good drug targets to eliminate the parasite without harming the host.
C)A comparison of mouse and human genomes would help reveal functions for previously unidentified human genes.
D)A comparison of human and mouse genomes would help observe DNA sequences that evolved prior to the evolution of mammals.

Question 45

Choose the true statements about pseudogenes.

A)Premature stop codons can produce pseudogenes.
B)Missense mutations can produce pseudogenes.
C)Pseudogenes have DNA sequences very similar to a functional gene.
D)Pseudogenes result from horizontal gene transfer.

Question 46

The best target for drug development would be

A)genes that are shared by humans and the organisms causing Chagas disease,African sleeping sickness,and Leishmania.
B)genes that are shared by the organisms causing Chagas disease and African sleeping sickness but not shared by humans or the organisms causing Leishmania.
C)genes that are shared by humans and the organisms causing Chagas disease but not the organisms causing African sleeping sickness or Leishmania.
D)genes that are shared by the organisms causing Chagas disease,African sleeping sickness,and Leishmania but not shared by humans.

Question 47

Hox genes are a family of transcription factors that regulate development throughout the animal kingdom.Studies of Hox genes in mice and Drosophila showed that many Hox genes are conserved between both species,and several Hox genes duplicated into new genes with novel functions within mice.Some Hox genes have even lost all function.Hox genes provide an example of which of the following? Check all that apply.

A)orthologs
B)paralogs
C)heterologues
D)pseudogenes

Question 48

What type of genes would be most likely to exhibit different expression patterns between humans and non-human primates,such as gorillas?

A)Genes controlling brain development
B)Genes controlling mammary gland development
C)Genes controlling lung development
D)Genes controlling heart development

Question 49

Plant species regularly hybridize in nature,but only some crosses result in new polyploid species.Of the crosses below,if each one occurred,which would be most likely to result in a new stable polyploid species?

A)A cross between a 2n gamete and a 1n gamete,forming a 3n hybrid.
B)A cross between a 4n gamete and a 1n gamete,forming a 5n hybrid.
C)A cross between a species with a CC genome and a species with a DD genome,forming a hybrid with a CD genome.
D)A cross between a species with a BB genome and a species with a DD genome,followed by a doubling of chromosomes,forming a hybrid with a BBDD genome.

Question 50

Recent research has suggested that some pseudogenes and non-protein-coding DNA code for RNAs that affect transcription of coding regions.This suggests that

A)pseudogenes code for proteins.
B)non-protein-coding DNA has no function.
C)non-protein-coding DNA may regulate gene expression.
D)pseudogenes have no function.

Question 51

Choose the true statement about genome size and gene number in animals.

A)There is a strong correlation between the number of genes and genome size.
B)Much of the extra DNA in humans is in the form of exons.
C)The pufferfish has a larger genome than humans and more genes.
D)Genome size differences depend to a large extent on the amount of retrotransposon DNA present.

Question 52

Choose the true statements about the role of genome analysis in crop improvement.Check all that apply.

A)Conservation of synteny will hinder our ability to find agriculturally important genes in plants.
B)Arabidopsis is being genetically modified as a crop plant.
C)Sequencing of the rice genome was important because it is related to many other cereal crop plants.
D)Insertion of genes from beneficial microbes into plant genomes can be used to improve crop yields.

Question 53

Genome sequencing of our human ancestor,Neanderthals (Homo neanderthalensis),revealed that Neanderthals have a FOXP2 gene with the same two amino acid changes observed in H.sapiens FOXP2.What can be concluded based on this finding? (Check all that apply)

A)Neanderthals evolved from H.sapiens.
B)H.sapiens evolved from Neanderthals.
C)Neanderthals may have had the ability to use language.
D)These two amino acid changes arose prior to the common ancestor of Neanderthals and H.sapiens.
E)Verbal speech was impossible for Neanderthals.

Question 54

Petrels (a flying and diving seabird)are thought to be one of the closest living relatives to penguins.What type of genes would be most likely to exhibit different expression patterns between these species?

A)Genes controlling skeletal development.
B)Genes regulating the digestive tract.
C)Genes regulating salt water tolerance.
D)Genes controlling organ development.