Chapter 25

Front 1

11. A major biological paradox is that genes are generally highly conserved and yet
A. there is very little difference among life forms existing today.
B. there is so much diversity among life forms existing today.
C. there are a huge number of ancestral genomes no matter how far back we look.
D. there are essentially identical development patterns in all species.
E. there is very little research into genomic sequences.

Back 1

B. there is so much diversity among life forms existing today.

Front 2

12. Genes with similar sequences in two different species, such as humans and mice
A. produce essentially identical products that have essentially identical functions.
B. may produce products that have slightly to dramatically different functions.
C. almost always have completely different functions in the two species.
D. there is no way of predicting whether the gene will function the same way or differently.
E. are nearly always nonfunctional or "nonsense" DNA in one of the species, present only as a transposon.

Back 2

B. may produce products that have slightly to dramatically different functions.

Front 3

13. The development of eyes has been intensively studied. Eyes of vertebrates and insects are
A. analogous (homoplastic), not homologous, yet the same Pax6 gene initiates development.
B. homologous, not analogous (homoplastic), yet the same Pax6 gene initiates development.
C. analogous (homoplastic), not homologous, and development is initiated by two different genes, Pax6 and Pax7.
D. homologous, not analogous (homoplastic), and development is initiated by two different genes, Pax6 and Pax7.

Back 3

A. analogous (homoplastic), not homologous, yet the same Pax6 gene initiates development.

Front 4

14. Regarding genome sequences and organismal development, it is important to remember that
A. development occurs almost exactly the same way in closely related species.
B. development takes longer in some species than in others, and this time factor is important.
C. gene sequence within a chromosome determines the timing of the gene expression.
D. timing plays an important part in genome sequencing.
E. changing the timing of gene expression can have dramatic changes in development.

Back 4

E. changing the timing of gene expression can have dramatic changes in development.

Front 5

15. The evolution of patterns on insect wings can be affected by all of the following functions except
A. species recognition.
B. protection from predation.
C. thermoregulation.
D. warning coloration.
E. aesthetics.

Back 5

E. aesthetics.

Front 6

16. One of the reasons why the model systems of yeast, Arabidopsis, nematode worms, fruit flies, and mice are so often used to study functional analysis of genes is because
A. they all have only a few chromosomes.
B. they are easy to cross with each other and observe polyploidy effects.
C. they have short life cycles.
D. they are easy to observe in the wild.
E. they mutate easily leading to new genomic variations.

Back 6

C. they have short life cycles.

Front 7

17. Eyes in mammals and _____________ are examples of convergent evolution.
A. eyespots in butterflies
B. compound eyes in fruit flies
C. eyes in great apes
D. eyes in fish

Back 7

B. compound eyes in fruit flies

Front 8

18. Eyes in different animal groups arose independently many times,
A. and the genes triggering lens formation in these different groups are homologous.
B. and the genes triggering lens formation in these different groups are homoplastic (analogous).
C. and the genes triggering lens formation in these different groups are examples of divergent evolution.
D. and the genes for eye color are multivariate.
E. and the genes for the eyes themselves are divergent.

Back 8

A. and the genes triggering lens formation in these different groups are homologous.

Front 9

19. The Pax6 gene, responsible for initiating lens formation in mice, can be inserted into fruit flies and
A. causes cancer of the brain as it tries to initiate a mammalian eye.
B. forms a partial eye since it is somewhat similar to the Pax7 gene of fruit flies.
C. will have no effect, indicating the extreme differences in lens formation.
D. can be expressed to initiate formation of an eye on the fruit fly's leg.
E. it is lethal to them.

Back 9

D. can be expressed to initiate formation of an eye on the fruit fly's leg.

Front 10

20. Experiments with ribbon worms and planaria have shown that
A. it is easy to hybridize the two species in nature.
B. Pax6-related genes are not always required for eye regeneration.
C. the DNA of each is sufficiently similar that they can be hybridized in a lab setting.
D. their eyes are examples of convergent evolution.

Back 10

C. the DNA of each is sufficiently similar that they can be hybridized in a lab setting.

Front 11

22. Experimental mutations in the timing of Hox expression cause lab mice to develop deformed limbs. This is an example of
A. evolution of a new gene to code for the new morphology.
B. homeosis.
C. heterochrony.
D. a change in spatial pattern of gene expression.

Back 11

C. heterochrony.

Front 12

24. The evolution of initiation of limb development in tetrapods is best explained by
A. a new gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 12

B. the modification of an existing gene for a new function.

Front 13

25. Unlike most rodents, capybaras typically have a very small tail or no tail. A possible explanation for this observation is
A. capybaras have two functional Brachyury genes.
B. capybaras have a nonfunctional Brachyury gene.
C. capybaras have a wild-type Brachyury gene.
D. capybaras have a Brachyury gene similar to the one found in ascidians.

Back 13

B. capybaras have a nonfunctional Brachyury gene.

Front 14

26. The evolution of development of snout-length in cichlid fish is best explained by
A. a single gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 14

A. a single gene mutation.

Front 15

27. The evolution of insect wing patterns is best explained by
A. a new gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 15

C. homoplastic convergence.

Front 16

28. The evolution of flower symmetry is best explained by
A. a new gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 16

C. homoplastic convergence.

Front 17

29. The evolution of petals through the AP3 gene is best explained by
A. a new gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 17

D. gene duplication and divergence.

Front 18

30. The evolution of cauliflower and broccoli from wild cabbage is best explained by
A. a single gene mutation.
B. the modification of an existing gene for a new function.
C. homoplastic convergence.
D. gene duplication and divergence.
E. conserved genes.

Back 18

A. a single gene mutation.

Front 19

If the stop codon in CAL evolved in the cauliflower lineage after broccoli and cauliflower had diverged from each other, it would be expected that

(Note the phylogeny is drawn with diagonal branches rather than the rectangular branches seen in the text.)

A. both broccoli and cauliflower flowers would be arrested as buds.
B. both broccoli and cauliflower would develop flowers normally.
C. broccoli would develop flowers normally, and cauliflower flowers would be arrested as buds.
D. cauliflower would develop flowers normally, and broccoli flowers would be arrested as buds.

Back 19

C. broccoli would develop flowers normally, and cauliflower flowers would be arrested as buds.

Front 20

32. Salamanders normally go through a juvenile stage in which they have external gills. Most salamanders lose these gills when they develop into adults, but axolotl salamanders retain gills into adulthood by suppressing gill development. This is an example of
A. gene duplication.
B. co-opting a gene for a new function.
C. homeosis.
D. heterochrony.

Back 20

D. heterochrony.

Front 21

37. AGAMOUS is a gene that has been implicated in the regulation of stamen formation in Arabidopsis flowers. If this is true, a mutant with a functional AP3 gene but a nonfunctional AGAMOUS gene would
A. produce petals but not stamens.
B. produce stamens but not petals.
C. produce petals and stamens.
D. not produce stamens or petals.

Back 21

A. produce petals but not stamens.

Front 22

39. Choose the functional gene experiment best demonstrating that the LFY gene is important in Arabidopsis flower production.
A. Delete LFY from the plant to create a mutant that produces deformed flowers. Reinsert the LFY sequence into the mutant, which will continue to produce deformed flowers.
B. Delete LFY from the plant to create a mutant that produces normal flowers. Reinsert the LFY sequence into the mutant, which will now produce deformed flowers.
C. Delete LFY from the plant to create a mutant that produces normal flowers. Reinsert the LFY sequence into the mutant, which will continue to produce normal flowers.
D. Delete LFY from the plant to create a mutant that produces deformed flowers. Reinsert the LFY sequence into the mutant, which will now produce normal flowers.

Back 22

D. Delete LFY from the plant to create a mutant that produces deformed flowers. Reinsert the LFY sequence into the mutant, which will now produce normal flowers.

Front 23

40. A scientist studying Astyanax mexicanus fish in the wild observes two seeing fish that produce an offspring without eyes. The best explanation for this observation is
A. genetic drift led to loss of eyes in this fish.
B. natural selection favored loss of eyes in this fish.
C. a mutation led to an increase in Pax6 expression in this fish.
D. a mutation led to a decrease in Pax6 expression in this fish.

Back 23

D. a mutation led to a decrease in Pax6 expression in this fish.

Front 24

42. If the Pax6 gene in a ribbon worm was replaced with planaria Pax6, then the ribbon worm would
A. not regenerate eyespots, because Pax6 does not function in eyespot regeneration in planaria.
B. not regenerate eyespots, because Pax6 functions in eyespot regeneration in planaria.
C. regenerate eyespots, because Pax6 functions in eyespot regeneration in planaria.
D. regenerate eyespots, because Pax6 does not function in eyespot regeneration in planaria.

Back 24

A. not regenerate eyespots, because Pax6 does not function in eyespot regeneration in planaria.

Front 25

A mutation in the transcription factor protein shown, protein T, disrupts the function of its DNA-binding motif. The most likely result of this mutation would be that

A. protein T can no longer directly interact with DNA, but it can still regulate gene expression through a second transcription factor.
B. protein T can no longer interact with other transcription factor proteins, but it can still regulate gene expression by directly binding to DNA.
C. protein T can no longer regulate gene expression.
D. protein T can still regulate gene expression by interacting directly with DNA regulatory regions.

Back 25

A. protein T can no longer directly interact with DNA, but it can still regulate gene expression through a second transcription factor.

Front 26

50. In order to test if the TLE gene is important in planaria tail regeneration, scientists cut a planaria in half longitudinally and blocked expression of TLE in the left half and allowed TLE expression in the right half. Which result would support that TLE is required for tail regeneration in planaria?
A. Neither half regenerates the tail.
B. Both halves regenerate the tail.
C. The right half regenerates the tail, and the left half does not.
D. The left half regenerates the tail, and the right half does not.

Back 26

C. The right half regenerates the tail, and the left half does not.