| DQ 23.1 |
“Every aspect of the genetic system raises an evolutionary question” (p. 657). What questions of this kind can you think of?
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| DQ 23.2 |
How can we study phenomena that evolved just once?
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| DQ 23.3 |
Give examples of features of the genetic system that may be accidental rather than adaptive.
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| DQ 23.4 |
Why do mutation rates not evolve to the values that would be best for the population?
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| DQ 23.5 |
Selection among species helps maintain sexual reproduction. Why is species selection not thought to be a major factor in explaining why sexual reproduction is widespread?
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| DQ 23.6 |
List the costs of sex. Which of these was an obstacle to the origin of sexual reproduction?
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| DQ 23.7 |
Weissman argued that sex is widespread because it generates variability that can be used by natural selection (p. 670). State this argument more precisely.
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| DQ 23.8 |
Can the Hill–Robertson effect explain why genetic diversity in abundant organisms is lower than expected? (pp. 368, 426).
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| DQ 23.9 |
Recent evidence shows that, in the human genome, recombination is concentrated into “hot spots” (p. 436). What might the consequences of this heterogeneity in recombination rate be?
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| DQ 23.10 |
In the previous chapter, we saw how reproductive isolation can evolve, such that recombination between populations is reduced. In this chapter, we saw how selection favors sexual interbreeding and recombination. How can these apparently opposing points of view be reconciled?
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| DQ 23.11 |
With sexual reproduction, selfish genetic elements can spread horizontally through the population (Fig. 21.4). How can sexual organisms reduce the harm done by such elements?
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| DQ 23.12 |
What are the evolutionary consequences of inbreeding depression?
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| DQ 23.13 |
What features of organisms make them more robust?
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