Bio 201 Levels of Selection I. As a rule, selection operates at the level of the individual. Possible exceptions to this rule include selection acting at the level of: a. genes b. groups c. populations d. species II. Selection at the level of the gene a. Certain genes can get themselves passed on to more than their fair share of offspring, even though they confer no fitness benefit to the individual. We call these ‘selfish genes’. b. What is segregation distortion? c. The t-allele is an allele in mice that can rapidly increase in frequency via segregation distortion. How does this process work? d. The t-allele is lethal in homozygotes. Can segregation distortion cause the t-allele to increase in frequency despite this large fitness cost? III. Selection at the level of the group. a. Imagine an allele ‘a’ that is at a high frequency in group 2, but is not found in group 1. If the ‘a’ allele allows all members of group 2 to produce more offspring or survive longer, can it increase in frequency? What if the ‘a’
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