Chapter 20 Multiple choice questions

What is the difference between forward and reverse genetics as methods to investigate the relationship between genes and behavior? Select correct answer.

In the first, genetic linkage analysis of family data is used, and in the other, genetic association using unrelated individuals

Both approaches use mutagenesis; the difference is the first employs random mutagenesis (chemicals such as ENU) and the other employs targeted mutagenesis (such as CRISPR)

Forward genetics analyses phenotypes associated with naturally occurring variation, and reverse genetics analyses phenotypes of artificially induced mutations

The two differ because one employs genetic analysis based on sequencing and the other uses genetic analysis derived from genotyping

Can a gene for which there is no evidence from genetic association studies of an effect on human behavior, be shown to have a large effect on mouse behavior through analysis of knockouts? Select all correct answers.

No, it is not possible since gene function is conserved through evolution

Yes, it is possible since the genetic effects on behavior are not necessarily the same in different mammalian species

Yes, it is possible because the two experimental designs are asking different questions

Yes, it is possible since naturally occurring genetic variants need not include genetic knockouts

Why do background genetic effects matter? Select all correct answers.

The genetic background effects may be as large or larger than the mutants that affect behavior, making mapping difficult

Genetic background effects, rather than a single large effect mutation, may explain the differences seen between two strains or populations

The potency with which a given background can mask or exacerbate the phenotype of a mutation underlines its relevance to the issue of genetic mechanism

Single-gene effects fade into quantitative genetics at the margins

Do genes have a specific effect on behavior? Select all correct answers.

Almost certainly not

The relationship between genes and behavior is contingent and indirect, making it impossible to talk of a gene 'for' a specific behavior

Yes, because genetic effects on behavior are often pleiotropic

Yes, when the mutation has a large effect

How do genes influence behavior? Select all correct answers.

Genetic effects on behavior depend on the environment

Genetic effects on behavior are pleiotropic

Genetic effects depend on the developmental stage, the tissue and the cell type in which they operate

Genetic effects on behavior can be explained by identifying the DNA sequence variants that give rise to behavioral variation

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