In Drosophila, Mutation Screening Usually Involves Use of a Balancer

question 18

Multiple Choice

In Drosophila, mutation screening usually involves use of a balancer chromosome that includes three elements: a set of overlapping inversions, an easily recognized dominant mutation, and a recessive lethal mutation that prevents balancer homozygotes from surviving. Which one, or combination, of these elements is necessary and sufficient to suppress crossovers?

• A) lethal recessive
• B) inversions plus dominant
• C) inversions
• D) lethal plus inversions
• E) dominants

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Definitions:

Observer Drift

A situation that occurs when at some point in the observation process the criteria the rater is using to respond to each item changes.

Systematic Error

A situation that occurs when a test being used consistently measures a domain other than the trait it was designed to assess.

Criteria

Standards or rules by which something can be judged or decided.

Range of Actions

The spectrum or variety of behaviors or activities an individual can perform or engage in.