Principles of Behavioral Genetics 1: Genetics basis review

Question 1

Central dogma in biology

Answer 1

DNA –transcription–> RNA –translation–> protein

Question 2

____ are the coding regions in a DNA sequence, while ____ are the noncoding regions

Answer 2

Exons; Introns

Question 3

____ ____ is a way that mix and match different exons and can go out of order, so a single ____ can actually code for several different ____ via different combinations

Answer 3

Alternative splicing; gene; proteins

Question 4

What are some ways that can affect protein synthesis?

Answer 4

1/ coding sequence variations: mutations like changes in the DNA which results in changes in the protein sequence
2/Variation in gene regulation: level/timing/place of expression, and alternative splicing

Question 5

An example of a protein coding effect is in the fur color of mice, where different ____ receptor 1 sequence results in different colors

Answer 5

melanocortin

Question 6

Two ways we can get variation in gene regulation is ____ ____ and ____ ____

Answer 6

regulatory elements; transcription factors

Question 7

What are regulatory elements?

Answer 7

Part of DNA sequence that doesn’t code for protein but affects how a protein-coding gene is expressed

Question 8

What is the difference between cis-regulatory element and trans-regulatory element?

Answer 8

cis-regulatory elements are closer to a gene, whereas trans-regulatory elements are far from a gene

Question 9

Examples of regulatory elements include ____, ____, and ____

Answer 9

promoters, enhancers, silencers

Question 10

What are transcription factors?

Answer 10

Peotein that bind to regulatory elements and can have an influence on when and how a target gene is expressed

Question 11

Leeper: Polarized
What is the correlation-causation problem?

Answer 11

Correlation doesn’t always mean there is a causation because there can always be confounders
“No causation without manipulation”

Question 12

Leeper: Polarized
Why is it hard to establish causation for a gene-behavior in humans?

Answer 12

• gene manipulation is not ethically ok
• can’t really manipulate the life experiences of an individual to see how they change
• Difficult to identify single gene of major effect on complex behavior (ex. human political leaning)
• humans are terrible model organisms

Question 13

Leeper: Polarized
Generally, how do twin studies work?

Answer 13

• Examine correlation between some behaioral measure in pairs of twins, and compare this correlation across groups (such as identical twins reared together/apart and fraternal twins reared together/apart)

Question 14

If ____ are important, then we should see ____ higher correlation in ____ twins vs. ____ twins, regardless of being reared together vs apart

Answer 14

genes; 2x; identical; fraternal

Question 15

Leeper: Polarized
What are some flaws with twin studies

Answer 15

• Twins reared together may be raised and socialized differently from others
• Twins reared apart shared an in utero environment
• Twin studies can’t reveal actual genetic cause but only a suggestion of relative strength of influence of gene vs environment

Question 16

Leeper: Polarized
Why is the study of political leaning especiallly problematic as a behavior of study

Answer 16

• Options are determined by culture (so largely environmental)
• Likely to change (unstable)
• No obvious adaptive/biolocial explaination to it
• No animal “models” of political leaning

Question 17

Carroll paper
What is pleiotropy?

Answer 17

When a single gene produces two apparently unrelated phenotypic effects

Question 18

Carroll paper
What is “The pleiotropy problem”?

Answer 18

If you get a deleterious mutation in a gene that is very important in not just one but many different functions, then you get a severely messed up animal – so really not a good idea to get mutations in key proteins…but then it limits manipulative ability

Question 19

Carroll paper
Evolution get around “The pleiotropy problem” through gene ____ (only mess with the copy version), gene ____ (change how the gene is regulated), and using different ____ of the gene (experiment different chunks of the gene without breaking your protein with a mutation)

Answer 19

duplication; regulation; isoforms

Question 20

King and Wilson proposed that the evolution that has taken place to distinguish between humans and apes has a lot to do with ____ changes rather than ____ ____ changes

Answer 20

regulatory; protein coding

Question 21

What is ascertainment bias?

Answer 21

It’s easier to identify and understand the nature of protein coding changes – regulatory changes may be just less studied

Question 22

Why regulatory changes can be a better way to influence phenotypes?

Answer 22

• “The pleiotropy problem”
• “break” regulatory element, the gene still works, only lose/alter some aspects of its regulation
• Can get more subtle & specific changes in how a gene is used